Short term viability of soft tissue detached from the skeleton of reef-building corals

We have induced soft tissue detachment from the skeleton of two colonial hard corals of the Pocilloporid family, both in vivo and in vitro. A parallel was made between polyp “bail-out”, i.e. field and laboratory-observed detachment of tissue fragments alone from the skeleton, and the dissociation method used for initiation of coral primary cell cultures. The in vitro approach provided insights into the active cellular re-arrangement mechanisms underlying coral tissue detachment. Functional polyps were not regenerated. Viability of tissue isolates detached from coral skeleton was probed for their use as a model for short-term biological assays. Cell viability dropped from 70% to 30% within the first week maintenance in vitro. Short-term isolate cultures limited to 3 days are a compromise allowing attachment of coral cells, yet preserving viability at about 70% of the total coral cell population.     

A simple temperature-based model predicts the upper latitudinal limit of the temperate coral Astrangia poculata

A few hardy ahermatypic scleractinian corals occur in shallow waters well outside of the tropics, but little is known concerning their distribution limits at high latitudes. Using field data on the growth of Astrangia poculata over an annual period near its northern range limit in Rhode Island, USA, we tested the hypothesis that the distribution of this coral is limited by low temperature. A simple model based on satellite sea surface temperature and field growth data at monthly temporal resolution was used to estimate annual net coral growth north and south of the known range limit of A. poculata. Annual net coral growth was the result of new polyp budding above ~10 °C minus polyp loss below ~10 °C, which is caused by a state of torpor that leads to overgrowth by encroaching and settling organisms. The model accurately predicted A. poculata’s range limit around Cape Cod, Massachusetts, predicting no net growth northward as a result of corals’ inability to counteract polyp loss during winter with sufficient polyp budding during summer. The model also indicated that the range limit of A. poculata coincides with a decline in the benefit of associating with symbiotic dinoflagellates (Symbiodinium B2/S. psygmophilum), suggesting that symbiosis may become a liability under colder temperatures. While we cannot exclude the potential role of other coral life history traits or environmental factors in setting A. poculata’s northern range limit, our analysis suggests that low temperature constrains the growth and persistence of adult corals and would preclude coral growth northward of Cape Cod.     

Studies on hydroid differentiation. VII. The hydrozoan stolon

The stolon of the colonial marine hydroid Podocoryne carnea differentiates sequentially as a function of age, forming four distinguishable regions characterized by epidermal cell differentiation: The Tip, New Stolon, Cnidogenic Masses, Old Stolon. Radioautographs of sections of colonies exposed to tritiated thymidine show that although cells of the epidermis and gastrodermis of the stolon incorporate the nucleoside into acid stable polynucleotide, cells of the stolon tips do not. Stolon extension is not, therefore, the result of a localized meristem-like growth zone. Stolon branching and new polyp formation are, similarly, not signaled by increased thymidine incorporation. The initial event heralding these morphogenetic activities appears to be the reorientation of epidermal cells along a new axis, and the acquisition of perisarc dissolving ability. This evidence is contraindicative of direct dependence of colony form on colony growth. The larger part of stolon epidermal cells are organized into cnidogenic masses where cnidocytes and possibly other amoebocytic cells are produced. Although no mitotic figures have been observed in gastroderm cells of the stolon, thymidine incorporation in this tissue occurs with the same frequency as it does in epidermis. Considerable numbers of gastroderm cells can be found in the gastric cavity. Frequently these and gastroderm cells in the stolon and polyps contain more than one nucleus.     

Polyp oriented modelling of coral growth

The morphogenesis of colonial stony corals is the result of the collective behaviour of many coral polyps depositing coral skeleton on top of the old skeleton on which they live. Yet, models of coral growth often consider the polyps as a single continuous surface. In the present work, the polyps are modelled individually. Each polyp takes up resources, deposits skeleton, buds off new polyps and dies. In this polyp oriented model, spontaneous branching occurs. We argue that branching is caused by a so called “polyp fanning effect” by which polyps on a convex surface have a competitive advantage relative to polyps on a flat or concave surface. The fanning effect generates a more potent branching mechanism than the Laplacian growth mechanism that we have studied previously (J. Theor. Biol. 224 (2003) 153). We discuss the application of the polyp oriented model to the study of environmentally driven morphological plasticity in stony corals. In a few examples we show how the properties of the individual polyps influence the whole colony morphology. In our model, the spacing of polyps influences the thickness of coral branches and the overall compactness of the colony. Density variations in the coral skeleton may also be important for the whole colony morphology, which we address by studying two variants of the model. Finally, we discuss the importance of small scale resource translocation in the coral colony and its effects on the morphology of the colony.     

Membrane Labeling of Coral Gastrodermal Cells by Biotinylation: The Proteomic Identification of Surface Proteins Involving Cnidaria-Dinoflagellate Endosymbiosis

The cellular and molecular-scale processes underlying the stability of coral-Symbiodinium endosymbioses remain unclear despite decades of investigation. As the coral gastroderm is the only tissue layer characterized by this unique symbiotic association, the membranes of these symbiotic gastrodermal cells (SGCs) may play important roles in the initiation and maintenance of the endosymbiosis. In order to elucidate the interactions between the endosymbiotic dinoflagellates and their coral hosts, a thorough characterization of SGC membranes is therefore required. Cell surface proteins of isolated SGCs were biotinylated herein by a cell impermeant agent, biotin-XX sulfosuccinimidyl ester. The in situ distribution of these biotinylated proteins was uncovered by both fluorescence and transmission electron microscopic imaging of proteins bound to Alexa Fluor® 488-conjugated streptavidin. The identity of these proteins was then determined by two-dimensional gel electrophoresis followed by liquid chromatography-tandem mass spectrometry. Nineteen (19) proteins were identified, and they are known to be involved in the molecular chaperone/stress response, cytoskeletal remodeling, and energy metabolism. These results not only reveal the molecular characters of the host SGC membrane, but also provide critical insight into understanding the possible role of host membranes in this ecologically important endosymbiotic association.     

Intraspecific contact and egg production in the massive coral Goniastrea aspera in Okinawa, subtropical Japan

The effect of intraspecific contact (Contact) on egg production was examined in the massive coral Goniastrea aspera in Okinawa, subtropical Japan. The contact was non-aggressive without damaging soft tissues each other. Within Contact colonies, polyp volume, polyp fertility (%polyps with gonad), and NE/PV (number of eggs per polyp volume) were significantly smaller in marginal (Mg) polyps without direct intraspecific contact than other polyps, but no difference was found between non-marginal and Mg-Contact (marginal with direct intraspecific contact) polyps. Comparisons of non-marginal polyps (non-marginal and Mg-Contact polyps were combined in Contact colonies) between Non-Contact and Contact colonies showed that fertility and NE/PV were significantly larger in Contact colonies than in Non-Contact colonies, but polyp volume were not different significantly. Further analyses dividing colonies at Non-Contact maturation colony size (60 polyps) revealed that fertility and NE/PV were significantly larger in Contact colonies than in Non-Contact colonies only in the small colonies (<60 polyps), indicating that the intraspecific contact promoted sexual maturation at smaller colony size; one polyped Contact coral was also reproductive. The lack of correlation between polyp volume and NE/PV in the small Contact colonies, and the similarity of NE/PV in non-marginal and Mg-Contact polyps within a colony, suggest that the maturation at smaller size in Contact colonies is realized by reproductive integration of polyps at the colony level. The present results show that size-structured populations such as colonial corals may show phenotypic diversity in key demographic parameters, such as reproductive output, dependent on ecological conditions.     

Efficacy of long-term coral tissue storage in ethanol for genotyping studies

With climate change threatening the future of coral reefs, there is an urgent need for effective coral tissue preservation and repositories from which DNA can be extracted. Most collections use 95 % ethanol as the storage medium, but its efficacy for long-term storage for short-fragment DNA use remains poorly documented. We conducted an accelerated DNA aging trial on three species of coral to ascertain whether ethanol-stored tissue and skeleton samples could yield fit-for-purpose DNA at time scales of 100+ yrs. We conclude that even using a crude DNA extraction technique, samples kept at 40 °C for 20 months yielded DNA of sufficient quality for Symbiodinium and coral host genotyping. If stored at ?20 °C, these samples are likely to still yield useable DNA after 100 yrs. Ethanol-stored samples compared favorably in terms of DNA quality, quantity and sample integrity with those stored in an analogue of the commercial storage buffer RNAlater ^®.     

IMPORTANCE OF MACRO‐ VERSUS MICROSTRUCTURE IN MODULATING LIGHT LEVELS INSIDE CORAL COLONIES1

Adjusting the light exposure and capture of their symbiotic photosynthetic dinoflagellates (genus Symbiodinium Freud.) is central to the success of reef‐building corals (order Scleractinia) across high spatio‐temporal variation in the light environment of coral reefs. We tested the hypothesis that optical properties of tissues in some coral species can provide light management at the tissue scale comparable to light modulation by colony architecture in other species. We compared within‐tissue scalar irradiance in two coral species from the same light habitat but with contrasting colony growth forms: branching Stylophora pistillata and massive Lobophyllia corymbosa. Scalar irradiance at the level of the symbionts (2 mm into the coral tissues) were <10% of ambient irradiance and nearly identical for the two species, despite substantially different light environments at the tissue surface. In S. pistillata, light attenuation (90% relative to ambient) was observed predominantly at the colony level as a result of branch‐to‐branch self‐shading, while in L. corymbosa, near‐complete light attenuation (97% relative to ambient) was occurring due to tissue optical properties. The latter could be explained partly by differences in photosynthetic pigment content in the symbiont cells and pigmentation in the coral host tissue. Our results demonstrate that different strategies of light modulation at colony, polyp, and cellular levels by contrasting morphologies are equally effective in achieving favorable irradiances at the level of coral photosymbionts.     

Bottlenecks to coral recovery in the Seychelles

Processes that affect recovery of coral assemblages require investigation because coral reefs are experiencing a diverse array of more frequent disturbances. Potential bottlenecks to coral recovery include limited larval supply, low rates of settlement, and high mortality of new recruits or juvenile corals. We investigated spatial variation in local abundance of scleractinian corals in the Seychelles at three distinct life history stages (recruits, juveniles, and adults) on reefs with differing benthic conditions. Following widespread coral loss due to the 1998 bleaching event, some reefs are recovering (i.e., relatively high scleractinian coral cover: ‘coral-dominated’), some reefs have low cover of living macrobenthos and unconsolidated rubble substrates (‘rubble-dominated’), and some reefs have high cover of macroalgae (‘macroalgal-dominated’). Rates of coral recruitment to artificial settlement tiles were similar across all reef conditions, suggesting that larval supply does not explain differential coral recovery across the three reef types. However, acroporid recruits were absent on macroalgal-dominated reefs (0.0 ± 0.0 recruits tile^?1) in comparison to coral-dominated reefs (5.2 ± 1.6 recruits tile^?1). Juvenile coral colony density was significantly lower on macroalgal-dominated reefs (2.4 ± 1.1 colonies m^?2), compared to coral-dominated reefs (16.8 ± 2.4 m^?2) and rubble-dominated reefs (33.1 ± 7.3 m^?2), suggesting that macroalgal-dominated reefs have either a bottleneck to successful settlement on the natural substrates or a high post-settlement mortality bottleneck. Rubble-dominated reefs had very low cover of adult corals (10.0 ± 1.7 %) compared to coral-dominated reefs (33.4 ± 3.6 %) despite no statistical difference in their juvenile coral densities. A bottleneck caused by low juvenile colony survivorship on unconsolidated rubble-dominated reefs is possible, or alternatively, recruitment to rubble-dominated reefs has only recently begun. This study identified bottlenecks to recovery of coral assemblages that varied depending on post-disturbance habitat condition.     

A Novel Method for Coral Explant Culture and Micropropagation

We describe here a method for the micropropagation of coral that creates progeny from tissue explants derived from a single polyp or colonial corals. Coral tissue explants of various sizes (0.5?C2.5?mm in diameter) were manually microdissected from the solitary coral Fungia granulosa. Explants could be maintained in an undeveloped state or induced to develop into polyps by manipulating environmental parameters such as light and temperature regimes, as well as substrate type. Fully developed polyps were able to be maintained for a long-term in a closed sea water system. Further, we demonstrate that mature explants are also amenable to this technique with the micropropagation of second-generation explants and their development into mature polyps. We thereby experimentally have established coral clonal lines that maintain their ability to differentiate without the need for chemical induction or genetic manipulation. The versatility of this method is also demonstrated through its application to two other coral species, the colonial corals Oculina patigonica and Favia favus.     

Ubiquitous associations and a peak fall prevalence between apicomplexan symbionts and reef corals in Florida and the Bahamas

Although apicomplexans are a widely recognized and important parasitic group, little is known about those associated with invertebrates, such as reef-building scleractinian corals. To resolve the potential impact of apicomplexans on coral health, it is first necessary to further describe this group of putative parasites and determine their prevalence among host species. Here, it was hypothesized that apicomplexan prevalence would vary seasonally, similar to what occurs in other marine apicomplexans as well as some coral symbionts. To test this, Caribbean scleractinian species Porites astreoides, Montastraea (=Orbicella) annularis, M. (=O.) faveolata, and Siderastrea siderea were sampled seasonally from two reefs each in the Florida Keys and the Bahamas for 9- and 5.5-year periods, respectively. Utilizing a PCR-based screening assay, apicomplexan DNA was detected from most Floridian (80.1 %: n = 555/693) and Bahamian (90.7 %: n = 311/343) coral tissue samples collected over these multi-year periods. Furthermore, apicomplexan DNA was detected from nearly all (98.7 %: n = 78/79) single polyps sampled at multiple locations within six M. faveolata colonies, indicating little to no intracolonial variation in the screening assay. Mixed-model logistic regression was utilized to determine the effects of season, host species, and reef on apicomplexan prevalence. The model identified a significant seasonal effect, with the highest apicomplexan prevalence occurring during fall. There also was a large effect of host species, with apicomplexan prevalence significantly lower among S. siderea colonies relative to the other species. While reef did not have a significant effect in the full model, there was a significant difference in apicomplexan prevalence between Floridian and Bahamian reefs for S. siderea, implying regional differences in this host species. Despite seasonal and species-specific differences in prevalence, apicomplexans are ubiquitous constituents of these particular scleractinian coral species from Florida and the Bahamas.     

IL-17和VEGF在慢性鼻-鼻窦炎患者鼻息肉组织中的表达及相关性研究

目的:探讨慢性鼻-鼻窦炎患者鼻息肉组织中白介素-17(IL-17)、血管内皮生长因子(VEGF)的表达,并分析IL-17、VEGF表达水平的相关性。方法:以我院2015年1月~2017年12月期间收治的慢性鼻-鼻窦炎患者95例为研究对象,按患者有无鼻息肉分为伴鼻息肉(观察1组)49例和不伴鼻息肉(观察2组)46例。另选取同期在我院进行治疗的鼻中隔偏曲患者40例为对照组。所有患者均进行鼻内镜手术治疗,并在术中取其较窄侧的鼻甲黏膜作为检测标本,采用免疫组化SP法检测各组织标本中的IL-17、VEGF的表达水平,并分析IL-17、VEGF表达水平的相关性。结果:观察1组患者IL-17、VEGF的阳性表达率分别为93.88%(46/49)、85.71%(42/49),均高于观察2组患者IL-17、VEGF的阳性表达率[76.09%(35/46)、65.22%(30/46)]以及对照组患者IL-17、VEGF的阳性表达率[5.00%(2/40)、2.50%(1/40)],差异均具有统计学意义(P0.05)。观察1组患者IL-17、VEGF的表达水平分别为(38.92±5.34)个/LP、(33.21±4.87)个/LP,均高于观察2组患者IL-17、VEGF的表达水平[(28.19±4.56)个/LP、(21.28±4.03)个/LP]以及对照组患者IL-17、VEGF的表达水平[(9.31±2.76)个/LP、(7.19±1.95)个/LP],差异均具有统计学意义(P0.05)。经Spearman相关性分析结果显示,观察1组患者、观察2组患者中,IL-17与VEGF的表达水平呈正相关性(P0.05)。结论:慢性鼻-鼻窦炎患者鼻息肉组织中IL-17、VEGF的表达显著升高,且IL-17与VEGF表达水平呈明显的正相关性,表明IL-17、VEGF可能共同参与鼻息肉的发生与发展过程。     

Ostracodes swallowed by Palaeozoic corals?

Middle Devonian heliolitids and favositids from Central Bohemia, belonging to Heliolites 'intermedius' LeMaitre and Favosites goldfussi Orbigny , incorporated ostracode shells within their living corallite structures. The ostracode shells were sealed in by skeletal tissue that was septal in origin (Heliolites) or they were roofed over by tabulae (Favosites). The foreign shell was near the axis of the polyp when trapped within the coral skeleton. Only ostracodes, not other rounded shells or sedimentary particles, were trapped in this way. Approximately one in 30 favositid corallites and one in 70 heliolitid corallites display this peculiar condition, where the ostracode shells seem to have been swallowed by the polyps. A probable scenario involves the injury of the mouth area and the trapping of the ostracodes. A high probability that the basal part of the polyp experienced a controlled penetration is the most striking part of the process. □ Favositids, heliolitids, ostracodes, coral growth violence, behavior, Middle Devonian, Bohemia.     

Coral overgrowth by an encrusting red alga (Ramicrusta sp.): a threat to Caribbean reefs?

An encrusting red alga (Ramicrusta sp., Peyssonneliaceae) present in Lac Bay, Bonaire, overgrows and kills corals and other sessile organisms. Living coral tissue comprises 7.2 % of the benthic composition of the shallow reef, while Ramicrusta sp. covers 18.7 % of the substratum. Of 1374 coral colonies surveyed, 45.8 % were partially overgrown by Ramicrusta sp., with P. porites, P. astreoides and M. complanata being the most susceptible to overgrowth. Mean Ramicrusta sp. maximum overgrowth rates ± SD were 0.08 ± 0.05 mm d^?1, 0.07 ± 0.03 mm d^?1 and 0.06 ± 0.02 mm d^?1 for M. complanata, P. porites and P. astreoides, respectively. None of the 71 coral recruits surveyed were growing on Ramicrusta sp. Ramicrusta sp. is an immediate threat to corals, reduces the area of suitable substratum for coral settlement and may have the ability to influence coral species composition.     

Genotype and attachment technique influence the growth and survival of line nursery corals

The Caribbean staghorn coral, Acropora cervicornis, was once a dominant habitat creating coral, but its populations have declined dramatically in recent decades. Numerous restoration efforts now utilize coral gardening techniques to cultivate this species, growing colonies on fixed structures or from line/suspended nurseries. Line nurseries have become increasingly popular because of their small footprint and ease of use, replacing fixed structures in many nurseries. To evaluate the efficacy of the line technique, this study evaluated growth, condition, and survivorship of A. cervicornis nursery colonies of three distinct genotypes grown via two line nursery techniques (suspended and direct line attachment [vertical]). Direct line attachment of nursery colonies resulted in poor survival (43%) and growth (9.5 ± 1.33 cm/year), whereas suspended culture had 100% survival and increased growth (61.1 ± 4.19 cm/year). Suspended culture had significantly reduced disease prevalence and prevented colony predation. Suspended coral growth was also comparable to a neighboring fixed structure nursery (55.2 ± 7.86 cm/year), and found to be as effective in propagating corals as fixed structures.     

Crown-of-thorns starfish predation and physical injuries promote brown band disease on corals

Brown band (BrB) disease manifests on corals as a ciliate-dominated lesion that typically progresses rapidly causing extensive mortality, but it is unclear whether the dominant ciliate Porpostoma guamense is a primary or an opportunistic pathogen, the latter taking advantage of compromised coral tissue or depressed host resistance. In this study, manipulative aquarium-based experiments were used to investigate the role of P. guamense as a pathogen when inoculated onto fragments of the coral Acropora hyacinthus that were either healthy, preyed on by Acanthaster planci (crown-of-thorns starfish; COTS), or experimentally injured. Following ciliate inoculation, BrB lesions developed on all of COTS-predated fragments (n = 9 fragments) and progressed up to 4.6 ± 0.3 cm d^?1, resulting in ~70 % of coral tissue loss after 4 d. Similarly, BrB lesions developed rapidly on experimentally injured corals and ~38 % of coral tissue area was lost 60 h after inoculation. In contrast, no BrB lesions were observed on healthy corals following experimental inoculations. A choice experiment demonstrated that ciliates are strongly attracted to physically injured corals, with over 55 % of inoculated ciliates migrating to injured corals and forming distinct lesions, whereas ciliates did not migrate to healthy corals. Our results indicate that ciliates characteristic of BrB disease are opportunistic pathogens that rapidly migrate to and colonise compromised coral tissue, leading to rapid coral mortality, particularly following predation or injury. Predicted increases in tropical storms, cyclones, and COTS outbreaks are likely to increase the incidence of coral injury in the near future, promoting BrB disease and further contributing to declines in coral cover.     

The effects of a coral disease on the reproductive output of Montastraea faveolata (Scleractinia: Faviidae)

The direct impacts of coral diseases on coral populations have been assessed by quantifying coral tissue loss and colony mortality, but the determination of the indirect effects of diseases, such as disruptions in life history functions (e.g. reproduction, growth and maintenance), are more difficult to ascertain and have been scant. This study involved a comparison of various measures of reproductive output from histological slides of healthy tissue samples of Montastraea faveolata and tissue samples from colonies with white plague (WP) infections in Dominica (West Indies). Although the variability in the reproductive data was high, WP had significant negative impacts on the percentage of reproductive polyps per cm2, the percentage of reproductive mesenteries within a polyp, oocyte quantity per polyp, mean oocyte volume (mm3), and fecundity (oocyte volume per cm2 of tissue). However, these effects were only observed in the tissue directly impacted by the WP disease "band" and were not observed in tissue samples taken 20 cm away from the lesion. Therefore, the effects of a coral disease (WP) on reproductive output are localized and not expressed colony-wide.     

Hydroxyapatite/regenerated silk fibroin scaffold-enhanced osteoinductivity and osteoconductivity of bone marrow-derived mesenchymal stromal cells

A novel hydroxyapatite/regenerated silk fibroin scaffold was prepared and investigated for its potential to enhance both osteoinductivity and osteoconductivity of bone marrow-derived mesenchymal stromal cells in vitro. Approx. 12.4 ± 0.06 % (w/w) hydroxyapatite was deposited onto the scaffold, and cell viability and DNA content were significantly increased (18.5 ± 0.6 and 33 ± 1.2 %, respectively) compared with the hydroxyapatite scaffold after 14 days. Furthermore, alkaline phosphatase activity in the novel scaffold increased 41 ± 2.5 % after 14 days compared with the hydroxyapatite scaffold. The data indicate that this novel hydroxyapatite/regenerated silk fibroin scaffold has a positive effect on osteoinductivity and osteoconductivity, and may be useful for bone tissue engineering.