Control Sponges Research Articles

Warm‐adapted sponges resist thermal stress by reallocating carbon and nitrogen resources from cell turnover to somatic growth

AbstractOcean warming will affect the functioning of coral reef ecosystems with unknown cascading effects. Any perturbation in the ability of sponges to recycle the dissolved organic matter released by primary producers and make it available to higher trophic levels, might have unknown consequences for the reef trophic chain. Biogeochemical processes were measured in the sponge Rhabdastrella globostellata from the semi‐enclosed lagoon of Bouraké, where temperatures reach 33.8°C and fluctuates by 6.5°C on a daily basis, and from a control reef (28°C). Using 13C‐ and 15N‐labeled coral mucus, we experimentally investigated to what extent high temperature affected the carbon (C) and nitrogen (N) resources allocation in the sponge tissue and detritus. Sponges from Bouraké maintained at 32°C incorporated more 13C‐ and 15N‐labeled coral mucus in the tissue and showed less detritus release when compared with sponges maintained at 28°C. In contrast, at 32°C control sponges showed lower 13C‐ and 15N‐labeled coral mucus incorporation in tissue and higher release of detritus. Our results suggest that sponges adapted to extreme temperatures of Bouraké were able to reallocate C and N resources from cell turnover to somatic growth and reduce tissue damage. In contrast, non‐adapted sponges at the control reef lack this mechanism and underwent tissue disintegration, highlighting the lethal effect of future warming. The change in C and N allocation in adapted sponges suggests a potential adaptation mechanism that allows R. globostellata to survive under thermal stress, but it could alter the availability of essential sources of energy with unknown consequences on the future reef trophic interactions.

Divergent morphological and microbiome strategies of two neighbor sponges to cope with low pH in Mediterranean CO2 vents

Ocean Acidification (OA) profoundly impacts marine biochemistry, resulting in a net loss of biodiversity. Porifera are often forecasted as winner taxa, yet the strategies to cope with OA can vary and may generate diverse fitness status. In this study, microbial shifts based on the V3–V4 16S rRNA gene marker were compared across neighboring Chondrosia reniformis sponges with high microbial abundance (HMA), and Spirastrella cunctatrix with low microbial abundance (LMA) microbiomes. Sponge holobionts co-occurred in a CO2 vent system with low pH (pHT ~ 7.65), and a control site with Ambient pH (pHT ~ 8.05) off Ischia Island, representing natural analogues to study future OA, and species' responses in the face of global environmental change. Microbial diversity and composition varied in both species across sites, yet at different levels. Increased numbers of core taxa were detected in S. cunctatrix, and a more diverse and flexible core microbiome was reported in C. reniformis under OA. Vent S. cunctatrix showed morphological impairment, along with signs of putative stress-induced dysbiosis, manifested by: 1) increases in alpha diversity, 2) shifts from sponge related microbes towards seawater microbes, and 3) high dysbiosis scores. Chondrosia reniformis in lieu, showed no morphological variation, low dysbiosis scores, and experienced a reduction in alpha diversity and less number of core taxa in vent specimens. Therefore, C. reniformis is hypothesized to maintain an state of normobiosis and acclimatize to OA, thanks to a more diverse, and likely metabolically versatile microbiome. A consortium of differentially abundant microbes was identified associated to either vent or control sponges, and chiefly related to carbon, nitrogen and sulfur-metabolisms for nutrient cycling and vitamin production, as well as probiotic symbionts in C. reniformis. Diversified symbiont associates supporting functional convergence could be the key behind resilience towards OA, yet specific acclimatization traits should be further investigated.

Responses of the temperate calcareous sponge Grantia sp. to ocean acidification

Abstract Sponges are important components of marine systems globally, and while sponges have generally been shown to tolerate ocean acidification (OA), most earlier studies have focused on demosponges with siliceous skeletons. In contrast, little is known of how calcareous sponges, with calcite or aragonite skeletons, may react to OA conditions. Here we measured tissue necrosis and respiration rate of the temperate New Zealand calcareous sponge Grantia sp. to simulated OA. Our treatment conditions were based on the IPCC RCP8.5 (pCO2 1131.9 ± 113 μatm) scenario over a 28 day experiment, and responses were compared to current day control conditions (pCO2 512.59 ± 23 μatm). Sponge respiration rate was not significantly different between the control and treatment sponges and there was no evidence of tissue necrosis over the course of the experiment. Overall, our study is consistent with earlier studies on demosponges, showing calcareous sponges to be resilient to OA.

Marine heatwave conditions drive carryover effects in a temperate sponge microbiome and developmental performance.

Marine heatwaves are increasingly subjecting organisms to unprecedented stressful conditions, but the biological consequences of these events are still poorly understood. Here we experimentally tested the presence of carryover effects of heatwave conditions on the larval microbiome, settlers growth rate and metamorphosis duration of the temperate sponge Crella incrustans. The microbial community of adult sponges changed significantly after ten days at 21°C. There was a relative decrease in symbiotic bacteria, and an increase in stress-associated bacteria. Sponge larvae derived from control sponges were mainly characterised by a few bacterial taxa also abundant in adults, confirming the occurrence of vertical transmission. The microbial community of sponge larvae derived from heatwave-exposed sponges showed significant increase in the endosymbiotic bacteria Rubritalea marina. Settlers derived from heatwave-exposed sponges had a greater growth rate under prolonged heatwave conditions (20 days at 21°C) compared to settlers derived from control sponges exposed to the same conditions. Moreover, settler metamorphosis was significantly delayed at 21°C. These results show, for the first time, the occurrence of heatwave-induced carryover effects across life-stages in sponges and highlight the potential role of selective vertical transmission of microbes in sponge resilience to extreme thermal events.

Body-Plan Reorganization in a Sponge Correlates with Microbiome Change.

Mounting evidence suggests that animals and their associated bacteria interact via intricate molecular mechanisms, and it is hypothesized that disturbances to the microbiome influence animal development. Here, we show that the loss of a key photosymbiont (i.e., bleaching) upon shading correlates with a stark body-plan reorganization in the common aquarium cyanosponge Lendenfeldia chondrodes. The morphological changes observed in shaded sponges include the development of a thread-like morphology that contrasts with the flattened, foliose morphology of control specimens. The microanatomy of shaded sponges markedly differed from that of control sponges, with shaded specimens lacking a well-developed cortex and choanosome. Also, the palisade of polyvacuolar gland-like cells typical in control specimens was absent in shaded sponges. The morphological changes observed in shaded specimens are coupled with broad transcriptomic changes and include the modulation of signaling pathways involved in animal morphogenesis and immune response, such as the Wnt, transforming growth factor β (TGF-β), and TLR-ILR pathways. This study provides a genetic, physiological, and morphological assessment of the effect of microbiome changes on sponge postembryonic development and homeostasis. The correlated response of the sponge host to the collapse of the population of symbiotic cyanobacteria provides evidence for a coupling between the sponge transcriptomic state and the state of its microbiome. This coupling suggests that the ability of animals to interact with their microbiomes and respond to microbiome perturbations has deep evolutionary origins in this group.

Wounding response in Porifera (sponges) activates ancestral signaling cascades involved in animal healing, regeneration, and cancer

Upon injury, the homeostatic balance that ensures tissue function is disrupted. Wound-induced signaling triggers the recovery of tissue integrity and offers a context to understand the molecular mechanisms for restoring tissue homeostasis upon disturbances. Marine sessile animals are particularly vulnerable to chronic wounds caused by grazers that can compromise prey’s health. Yet, in comparison to other stressors like warming or acidification, we know little on how marine animals respond to grazing. Marine sponges (Phylum Porifera) are among the earliest-diverging animals and play key roles in the ecosystem; but they remain largely understudied. Here, we investigated the transcriptomic responses to injury caused by a specialist spongivorous opisthobranch (i.e., grazing treatment) or by clipping with a scalpel (i.e., mechanical damage treatment), in comparison to control sponges. We collected samples 3 h, 1 d, and 6 d post-treatment for differential gene expression analysis on RNA-seq data. Both grazing and mechanical damage activated a similar transcriptomic response, including a clotting-like cascade (e.g., with genes annotated as transglutaminases, metalloproteases, and integrins), calcium signaling, and Wnt and mitogen-activated protein kinase signaling pathways. Wound-induced gene expression signature in sponges resembles the initial steps of whole-body regeneration in other animals. Also, the set of genes responding to wounding in sponges included putative orthologs of cancer-related human genes. Further insights can be gained from taking sponge wound healing as an experimental system to understand how ancient genes and regulatory networks determine healthy animal tissues.

Topical Vancomycin and Risk of Sternal Wound Infections: A Double-Blind Randomized Controlled Trial

BackgroundThe use of topical vancomycin in the reduction of sternal wound infection (SWI) risk has become a point of contention. The earlier literature consists of observational studies and 1 unblinded trial. Hence, the objective of this study was to assess whether vancomycin reduces the incidence of SWI in a double-blind randomized controlled trial. MethodsPatients were randomized 1:1 to either vancomycin-soaked (vancomycin) or saline-soaked (control) sponges. The sponges were applied once the sternum was opened and were removed just before sternal closure. Patients were followed up at 3 months and at 1 year postoperatively to determine the incidence of SWI in each group. Results were analyzed according to the modified intention-to-treat principle. ResultsThis study assessed 1038 patients for eligibility and enrolled 1037 patients. There were 517 patients randomized to the vancomycin group and 520 patients randomized to the control group. Analysis was performed on 1021 patients. At 3 months postoperatively, there was no significant difference in the incidence of SWI between the vancomycin and control groups (2.7% vs 4.1%; P = .23). There was also no significant difference between the vancomycin and control groups in the risk of superficial, deep, and organ-space infections. Similar findings were observed 1 year postoperatively. The most common organism isolated was coagulase-negative Staphylococcus. ConclusionsThe use of vancomycin applied to the sternum during cardiac surgery does not reduce the incidence of SWI.

Short-term physiological responses of the New Zealand deep-sea sponge Ecionemia novaezealandiae to elevated concentrations of suspended sediments

The generation of sediment plumes by human activities, such as bottom fishing and potential deep-sea mining, poses threats to deep-sea benthic fauna. Sponges are important components of deep-sea ecosystems and can be particularly sensitive to elevated suspended sediment concentrations. In this study, we exposed the deep-sea New Zealand sponge Ecionemia novaezealandiae (Dendy, 1924) (Demospongiae: Ancorinidae) to a range of suspended sediment concentrations (SSC) (32, 78 and 475 mg l−1) and control conditions (no added sediment) continuously for two weeks. Survival was high (97%), with only one death (at the highest SSC). Half of the sponges in the 475 mg l−1 treatment showed partial necrosis by the end of the two-week exposure. Respiration rates of sponges in the sediment addition treatments decreased relative to control sponges by 27, 37 and 60%, respectively, after day 1; and by 7, 17, and 27%, respectively, after 14 days of suspended sediment exposure. At the end of the experiment, sectioning of the sponges revealed sediments deep in the tissue of all specimens, including controls, indicating previous incorporation of sediment occurred in their natural environment. Despite the high survival, the decreased respiration rates and partial necrosis with increasing SSC indicated a decline in sponge condition that could affect this species beyond the disturbance period.

Testing of how and why the Terpios hoshinota sponge kills stony corals

An encrusting sponge, Terpios hoshinota, has the potential to infect all species of stony corals in shallow reefs and killing them. It caused a decline in coral coverage in two south-eastern islands of Taiwan. We proposed two hypotheses to examine how the sponges kill the corals, namely, light blocking and toxins, and tested by in-situ experiments. The results revealed that both light blocking, sponge toxins, and particularly the combination of both factors were effective at inducing tissue damage in stony corals over a short period. Second, to answer why the sponges killed the corals, we tested two hypotheses, namely, gaining nutrients versus gaining substrates for the sponge. By analyzing the stable isotopes 13C and 15N, as well as exploiting an enrichment experiment, it was possible to determine that only approximately 9.5% of the carbon and 16.9% of the nitrogen in the newly grown sponge tissues originated from the enriched corals underneath. The analysis also revealed that the control corals without isotope enrichment had higher δ13C and δ15N than the control sponges, which was an additional indication that T. hoshinota did not rely heavily on corals for nutrients. Therefore, our results support the hypothesis that the encrusting sponge did not kill corals for food or nutrients, but rather for the substrate.

The Effect of Depth on the Morphology, Bacterial Clearance, and Respiration of the Mediterranean Sponge Chondrosia reniformis (Nardo, 1847)

To support the successful application of sponges for water purification and collagen production, we evaluated the effect of depth on sponge morphology, growth, physiology, and functioning. Specimens of Eastern Mediterranean populations of the sponge Chondrosia reniformis (Nardo, 1847) (Demospongiae, Chondrosiida, Chondrosiidae) were reciprocally transplanted between 5 and 20 m depth within the Kaş-Kekova Marine Reserve Area. Control sponges at 5 m had fewer but larger oscula than their conspecifics at 20 m, and a significant inverse relationship between the osculum density and size was found in C. reniformis specimens growing along a natural depth gradient. Sponges transplanted from 20 to 5 m altered their morphology to match the 5 m control sponges, producing fewer but larger oscula, whereas explants transplanted from 5 to 20 m did not show a reciprocal morphological plasticity. Despite the changes in morphology, the clearance, respiration, and growth rates were comparable among all the experimental groups. This indicates that depth-induced morphological changes do not affect the overall performance of the sponges. Hence, the potential for the growth and bioremediation of C. reniformis in mariculture is not likely to change with varying culture depth. The collagen content, however, was higher in shallow water C. reniformis compared to deeper-growing sponges, which requires further study to optimize collagen production.

Baikal endemic sponges in the system of ecological monitoring

Within the framework of the monitoring of the Baikal endemic sponge fauna, which was started in 2015, we organized field observations. This study is aimed to investigate the dynamics of the disease incidence in sponges and the rate of their degradation/regeneration in the natural environment within a limited space. The observations of the tagged sponges having different shapes were carried out using the photo and video method. Thus, from 2016 to 2018, there was a deterioration dynamics in the state of most control sponges. From 2018 to 2019, the state of some sponges improved owing to the regeneration of the affected areas of the body. In this study, we revealed that Baikal sponges with encrusted and globulous shapes could recover very quickly owing to the regeneration of the affected areas and the rapid growth of the body. After almost complete degradation of the body in the encrusted sponge, the fragments remain, which can subsequently grow as individual specimens. Similar observations are currently being conducted throughout Lake Baikal.

A controlled aquarium system and approach to study the role of sponge-bacteria interactions using Aplysilla rosea and Vibrio natriegens

Sponge-bacteria interactions are very important due to their ecological and biological significance. To understand the impact of interactions between sponges and bacteria (both associated with and external to sponges) on sponge-associated microbial diversity, sponge metabolite profiles and bioactivity, we used a controlled aquarium system and designed an experimental approach that allows the study of sponge-bacteria interactions in a well-defined manner. To test the feasibility of this approach, this system was used to study the interaction between a sponge Aplysilla rosea and a marine bacterium commonly found in seawater, Vibrio natriegens. Sponge explants were exposed to V. natriegens, at 5 × 106 cfu/ml, and changes were monitored for 48 hours. Pyro-sequencing revealed significant shifts in microbial communities associated with the sponges after 24 to 48 hours. Both the control (sponge only without added bacteria) and Vibrio-exposed sponges showed a distinct shift in bacterial diversity and abundance with time. Vibrio exposure significantly increased bacterial diversity, the abundance of a number of taxa compared to control sponges. The result experimentally supports the notion of dynamic and concerted responses by the sponge when interacting with a bacterium, and demonstrates the feasibility of using this controlled aquarium system for the study of sponge-bacteria interactions.

Warfarin affects acute inflammatory response induced by subcutaneous polyvinyl sponge implantation in rats

Purpose: Warfarin (WF) is an anticoagulant which also affects physiological processes other than hemostasis. Our previous investigations showed the effect of WF which gained access to the organism via skin on resting peripheral blood granulocytes. Based on these data, the aim of the present study was to examine whether WF could modulate the inflammatory processes as well. To this aim the effect of WF on the inflammatory response induced by subcutaneous sponge implantation in rats was examined.Materials and methods: Warfarin-soaked polyvinyl sponges (WF-sponges) were implanted subcutaneously and cell infiltration into sponges, the levels of nitric oxide (NO) and inflammatory cytokines tumor necrosis factor (TNF) and interleukin-6 (IL-6) production by sponge cells were measured as parameters of inflammation. T cell infiltration and cytokine interferon-γ (IFN-γ), interleukin-17 (IL-17) and interleukin-10 (IL-10) were measured at day 7 post implantation.Results: Warfarin exerted both stimulatory and suppressive effects depending on the parameter examined. Flow cytometry of cells recovered from sponges showed higher numbers of granulocytes (HIS48+ cells) at days 1 and 3 post implantation and CD11b+ cells at day 1 compared to control sponges. Cells from WF-sponges had an increased NO production (Griess reaction) at days 1 and 7. In contrast, lower levels of TNF (measured by ELISA) production by cells recovered from WF-soaked sponges were found in the early (day one) phase of reaction with unchanged levels at other time points. While IL-6 production by cells recovered from WF-soaked sponges was decreased at day 1, it was increased at day 7. Higher T cell numbers were noted in WF sponges at day 7 post implantation, and recovered cells produced more IFN-γ and IL-17, while IL-10 production remained unchanged.Conclusions: Warfarin affects some of the parameters of inflammatory reaction induced by subcutaneous polyvinyl sponge implantation. Differential (both stimulatory as well as inhibitory) effects of WF on inflammatory response to sponge implants might affect the course and/or duration of this reaction.

The role of sponge-bacteria interactions: the sponge Aplysilla rosea challenged by its associated bacterium Streptomyces ACT-52A in a controlled aquarium system.

Sponge-associated bacteria play a critical role in sponge biology, metabolism and ecology, but how they interact with their host sponges and the role of these interactions are poorly understood. This study investigated the role of the interaction between the sponge Aplysilla rosea and its associated actinobacterium, Streptomyces ACT-52A, in modifying sponge microbial diversity, metabolite profile and bioactivity. A recently developed experimental approach that exposes sponges to bacteria of interest in a controlled aquarium system was improved by including the capture and analysis of secreted metabolites by the addition of an absorbent resin in the seawater. In a series of controlled aquaria, A. rosea was exposed to Streptomyces ACT-52A at 106cfu/ml and monitored for up to 360h. Shifts in microbial communities associated with the sponges occurred within 24 to 48h after bacterial exposure and continued until 360h, as revealed by TRFLP. The metabolite profiles of sponge tissues also changed substantially as the microbial community shifted. Control sponges (without added bacteria) and Streptomyces ACT-52A-exposed sponges released different metabolites into the seawater that was captured by the resin. The antibacterial activity of compounds collected from the seawater increased at 96 and 360h of exposure for the treated sponges compared to the control group due to new compounds being produced and released. Increased antibacterial activity of metabolites from treated sponge tissue was observed only at 360h, whereas that of control sponge tissue remained unchanged. The results demonstrate that the interaction between sponges and their associated bacteria plays an important role in regulating secondary metabolite production.

Chitosan–hyaluronic acid/VEGF loaded fibrin nanoparticles composite sponges for enhancing angiogenesis in wounds

Reduced levels of endogenous growth factors and diminished angiogenesis are contributory factors for impaired wound healing in diabetic patients. Vascular endothelial growth factor (VEGF) is the most potent angiogenic growth factor which stimulates multiple phases of wound healing angiogenesis and thereby accelerates healing. The aim of this work was to develop chitosan–hyaluronic acid composite sponge incorporated with fibrin nanoparticles loaded with VEGF as a wound dressing for diabetic wounds. VEGF loaded fibrin nanoparticles (150–180nm) were prepared and characterized which were then incorporated to the composite sponge. The prepared sponges were characterized by SEM and FT-IR. Porosity, swelling, biodegradation, mechanical properties and haemostatic potential of the sponges were also studied. Release of VEGF from the composite sponges was evaluated using ELISA kit. More than 60% of the loaded VEGF was released in three days. Cell viability and attachment studies of the composite sponges were evaluated using human dermal fibroblast (HDF) cells and human umbilical vein endothelial cells (HUVECs). HUVECs seeded on VEGF containing sponges showed capillary like tube formation which was absent in control sponges. The results suggest that the prepared chitosan–hyaluronic acid/VEGF loaded nanofibrin composite sponges (CHVFS) have potential to induce angiogenesis in wound healing.

1,25-Dihydroxyvitamin D3 Suppresses Telomerase Expression and Human Cancer Growth through MicroRNA-498

Telomerase is an essential enzyme that counteracts the telomere attrition accompanying DNA replication during cell division. Regulation of the promoter activity of the gene encoding its catalytic subunit, the telomerase reverse transcriptase, is established as the dominant mechanism conferring the high telomerase activity in proliferating cells, such as embryonic stem and cancer cells. This study reveals a new mechanism of telomerase regulation through non-coding small RNA by showing that microRNA-498 (miR-498) induced by 1,25-dihydroxyvitamin D3 (1,25(OH)(2)D(3)) decreases the mRNA expression of the human telomerase reverse transcriptase. MiR-498 was first identified in a microarray analysis as the most induced microRNA by 1,25(OH)(2)D(3) in ovarian cancer cells and subsequently validated by quantitative polymerase chain reaction assays in multiple human cancer types. A functional vitamin D response element was defined in the 5-prime regulatory region of the miR-498 genome, which is occupied by the vitamin D receptor and its coactivators. Further studies showed that miR-498 targeted the 3-prime untranslated region of human telomerase reverse transcriptase mRNA and decreased its expression. The levels of miR-498 expression were decreased in malignant human ovarian tumors as well as human ovarian cancer cell lines. The ability of 1,25(OH)(2)D(3) to decrease human telomerase reverse transcriptase mRNA and to suppress ovarian cancer growth was compromised when miR-498 was depleted using the sponges in cell lines and mouse tumor models. Taken together, our studies define a novel mechanism of telomerase regulation by small non-coding RNAs and identify miR-498 as an important mediator for the anti-tumor activity of 1,25(OH)(2)D(3).

Shifts in microbial and chemical patterns within the marine sponge Aplysina aerophoba during a disease outbreak

The microbial community composition in affected and unaffected portions of diseased sponges and healthy control sponges of Aplysina aerophoba was assessed to ascertain the role of microbes in the disease process. Sponge secondary metabolites were also examined to assess chemical shifts in response to infection. The microbial profile and aplysinimine levels in unaffected tissue near the lesions closely reflected those of healthy sponge tissue, indicating a highly localized disease process. DGGE detected multiple sequences that were exclusively present in diseased sponges. Most notably, a Deltaproteobacteria sequence with high homology to a coral black band disease strain was detected in all sponge lesions and was absent from all healthy and unaffected regions of diseased sponges. Other potential pathogens identified by DGGE include an environmental Cytophaga strain and a novel Epsilonproteobacteria strain with no known close relatives. The disease process also caused a major shift in prokaryote community structure at a very high taxonomic level. Using 16S rRNA gene sequence analysis, only the diseased sponges were found to contain sequences belonging to the Epsilonproteobacteria and Firmicutes, and there was a much greater number of Bacteroidetes sequences within the diseased sponges. In contrast, only the healthy sponges contained sequences corresponding to the cyanobacteria and 'OP1' candidate division, and the healthy sponges were dominated by Chloroflexi and Gammaproteobacteria sequences. Overall bacterial diversity was found to be considerably higher in diseased sponges than in healthy sponges. These results provide a platform for future cultivation-based experiments to isolate the putative pathogens from A. aerophoba and perform re-infection trials to define the disease aetiology.

Phototrophic nutrition and symbiont diversity of two Caribbean sponge–cyanobacteria symbioses

Coral reef sponges frequently harbor symbiotic cyanobacteria that can potentially ben- efit their hosts by providing supplemental nutrition. Although nutritional mutualisms have been doc- umented for Indo-Pacific sponges, previous investigations suggest that Caribbean sponges obtain no nutritional benefits from their symbionts. We conducted field-based shading experiments to deter- mine the effects of reduced irradiance on symbiont abundance and host growth in the Caribbean coral reef sponges Aplysina fulva and Neopetrosia subtriangularis, both of which host the unicellular cyanobacterium Synechococcus spongiarum. For both host species, 6 wk of shading significantly reduced chlorophyll a concentrations to less than half of those in control sponges. Shaded A. fulva individuals exhibited less than half the growth of control sponges. For N. subtriangularis, no signifi- cant differences in growth rates were observed between shaded and control sponges. Measurements of gross photosynthesis to respiration (P:R) ratios predicted that both host sponges were heterotrophic at low irradiances ( 500 µmol m -2 s -1 ), with measurements obtained at high irradiances likely to be more indicative of natural conditions. Phylo- genetic analyses of cyanobacterial internal transcribed spacer (ITS) ribosomal RNA gene sequences revealed 3 genetically distinct clades of S. spongiarum (designated A, B and C). Clade A symbionts were isolated exclusively from A. fulva, Clade B symbionts from both host sponge species and Clade C symbionts exclusively from N. subtriangularis. These findings demonstrate that Caribbean sponges associate with diverse clades of cyanobacterial symbionts that may confer variable nutritional bene- fits; in some cases, these symbionts appear to substantially enhance host growth rates.

Contrast‐enhanced MRI of murine sponge model for progressive angiogenesis assessed with gadoteridol (ProHance) and gadocoletic acid trisodium salt (B22956/1)

To investigate the potential value of MRI for noninvasive assessment of angiogenesis in a murine model exploiting the properties of two contrast agents, gadoteridol (ProHance) and gadocoletic acid trisodium salt (B22956/1). Biocompatible sponges were implanted in both mice flanks. Stimulated sponges contained human recombinant basic fibroblast growth factor (bFGF) as the angiogenic agent; control sponges contained vehicle. Angiogenesis was evaluated by MRI after injection of extravascular (ProHance) or blood-pool (B22956/1) contrast agents at different times after sponge implantation. Sponges signal intensity enhancement was calculated both as the relative enhancement and the rate of relative enhancement. Results from MRI were validated by classic biochemical (hemoglobin level and protein content) and morphological (histology) assays. The intrinsic different properties of ProHance and B22956/1 in wash-in and wash-out kinetics were useful to detect progressive vascularization and the establishment of a functional vascular network in the implants. Moreover, MRI allowed the appreciation of differences in neovessel colonization between bFGF-treated sponges and controls. Hemoglobin level, protein content, and histology confirmed the sponge vascularization and MRI results. Contrast-enhanced MRI is a reliable tool to study vascular characteristics in animal models of angiogenesis. The different kinetic properties of contrast agents can provide evidence of different functional neovascularization aspects and levels.

Cbfa1/Runx2‐deficiency delays bone wound healing and locally delivered Cbfa1/Runx2 promotes bone repair in animal models

Core binding factor 1 (Cbfa1)/runt-related transcription factor 2 (Runx2) has been identified as a "master gene" in osteoblastic differentiation. In this two-part study, part I of the study was undertaken to test the hypothesis that bone regeneration is compromised in Cbfa1+/- mice. Compared with wild-type mice, wound healing was dramatically delayed in Cbfa1+/- mice characterized by the presence of a small amount of bone near the base of the wounds. The bone defects were largely filled with fibrous connective tissues 3 weeks after surgery. Part II was performed to determine the effects of Cbfa1 in enhancing bone wound healing using a gene-activated matrix (GAM) method. Cbfa1 cDNA was mixed with a biodegradable bovine type I collagen sponge and was inserted into the periodontal window wounds of mice. Control sponges were collagen matrix without Cbfa1 cDNA. Histological analysis and immunohistochemical staining demonstrated that compared with controls, there was increased new bone formation that almost filled the wound defects 14 days after surgery in the Cbfa1-GAM group. The collagen sponge matrix did not seem to elicit significant foreign body reaction in either group. In conclusion, the reduced expression of Cbfa1 interferes with the process of bone wound healing, and local application of Cbfa1 cDNA incorporated into a collagen matrix promotes bone tissue regeneration.