Search Results (17)

In this study, we used a culture-dependent approach to explore the biochemical potential of bacteria associated with two genera of soft corals collected from the Red Sea (phylum Cnidaria, class Anthozoa, subclass Octocorallia, order Alcyonaceae, and family Alcyoniidae). The soft corals were identified as Cladiella sp. and Paralemnalia sp. The associated bacteria were isolated on marine agar, nutrient agar, starch casein agar, ISP2 Agar, and M1 agar. The highest proportion of strains was recovered using marine agar, followed by nutrient agar and M1. We focused on Gram-positive bacteria and evaluated their cytotoxicity and antimicrobial activity. About 24% of the bacterial samples demonstrated promising cytotoxicity against Ehrlich ascites carcinoma (EAC). Out of 12 bioactive isolated strains, two bacterial isolates showed strong cytotoxicity, with IC₅₀ values of 134.47 and 148.5 µg/mL, respectively. Nine isolates displayed significant antimicrobial activity against two tested pathogens. Based on the 16S rRNA gene sequence, two bioactive bacterial isolates were identified as Bacillus subtilis and Microbacterium sp. These findings indicate that bacteria associated with soft corals could be a valuable source of new bioactive compounds with potential uses in drug development. Furthermore, our data add important insights to the understudied field of host-microbiome relationships in soft corals. Full article

The soft coral order Alcyonacea is a common coral found in the deep sea and plays a crucial role in the deep-sea ecosystem. This study aims to predict the distribution of Alcyonacea in the western Pacific Ocean using four machine learning-based species distribution models. The performance of these models is also evaluated. The results indicate a high consistency among the prediction results of the different models. The soft coral order is primarily distributed in the Thousand Islands Basin, Japan Trench, and Thousand Islands Trench. Water depth and silicate content are identified as important environmental factors influencing the distribution of Alcyonacea. The RF, Maxent, and XGBoost models demonstrate high accuracies, with the RF model exhibiting the highest prediction accuracy. However, the Maxent model outperforms the other three models in data processing. Developing a high-resolution, high-accuracy, and high-precision habitat suitability model for soft corals can provide a scientific basis and reference for China’s exploration and research in the deep sea field and aid in the planning of protected areas in the high seas. Full article

The Red Sea is a suitable model for studying coral reefs under climate change due to its strong environmental gradient that provides a window into future global warming scenarios. For instance, corals in the southern Red Sea thrive at temperatures predicted to occur at the end of the century in other biogeographic regions. Corals in the Red Sea thrive under contrasting thermal and environmental regimes along their latitudinal gradient. Because microbial communities associated with corals contribute to host physiology, we conducted a systematic review of the known diversity of Red Sea coral-associated bacteria, considering geographic location and host species. Our assessment comprises 54 studies of 67 coral host species employing cultivation-dependent and cultivation-independent techniques. Most studies have been conducted in the central and northern Red Sea, while the southern and western regions remain largely unexplored. Our data also show that, despite the high diversity of corals in the Red Sea, the most studied corals were Pocillopora verrucosa, Dipsastraea spp., Pleuractis granulosa, and Stylophora pistillata. Microbial diversity was dominated by bacteria from the class Gammaproteobacteria, while the most frequently occurring bacterial families included Rhodobacteraceae and Vibrionaceae. We also identified bacterial families exclusively associated with each of the studied coral orders: Scleractinia (n = 125), Alcyonacea (n = 7), and Capitata (n = 2). This review encompasses 20 years of research in the Red Sea, providing a baseline compendium for coral-associated bacterial diversity. Full article

Coral reefs provide a habitat for many marine organisms and support the safety, coastal protection, well-being, and food and economic security of hundreds of millions of people. The focus on coral species diversity cannot be overemphasized. One of them, Astrogorgia, contains many marine natural active substances, and has important scientific research value and application prospects. Most of the current research on the active substances of the genus Astrogorgia is based on unidentified species, and in-depth taxonomic studies are urgently needed. A total of 1185 samples were collected from 2014 to 2021 in the waters of Xiamen Bay. Herein, the morphological identification, electronic microscopy, and gene fragment sequencing methods were used for the taxonomic study. There are three species of Astrogorgia identified, including Astrogorgia lafoa, A. arborea, and A. dumbea. Among them, A. lafoa and A. arborea are newly recorded species in the waters of China. A. lafoa is distributed in Qingyu Island, A. arborea is distributed in Wuyu Island, and A. dumbea is widely distributed in Baiha Reef, Qingyu Island, Wuyu Island, and Xiaobai Island. In this paper, the geographical distribution and the habits of 18 species of Astrogorgia are summarized, and the evolution of family and genus classification of Astrogorgia is discussed. The results enrich the geographical distribution information and coral species diversity records of Astrogorgia in China. Full article

Among Mediterranean habitat-forming alcyonaceans, the sea fan Eunicella verrucosa is known to form dense forests at circalittoral depths, providing seascape complexity and sustaining a rich associated fauna. Its occurrence in the Tavolara–Punta Coda Cavallo Marine Protected Area (NE Sardinia) has never been deeply investigated despite this area being well known from a biocoenotic point of view. This study provides new information on the size of the colonies settled between 35 and 59 m depth on granitic outcrops and represents a contribution to highlighting the hotspot of megabenthic diversity enclosed in the protected area. The presence of 100 colonies was assessed by photographic samplings performed between 2015 and 2020, in a small area characterized by peculiar ecological conditions. The morphometric descriptions and age estimation showed a persistently isolated population probably derived from a stochastic event of settling of larvae presumably coming from the Tuscany Archipelago. A richly associated epibiotic community, composed of 18 species/OTUs, showed how branched bryozoans, particularly Turbicellepora avicularis, and the parasitic octocoral Alcyonium coralloides, affected the colonies’ branches, suggesting a putative anthropogenic impact related to fishing activity. This study indicates that proper protection and management strategies are mandatory for the Marine Protected Area, in order to conserve this unique population and the whole associated benthic assemblage. Full article

Coral forests are vulnerable marine ecosystems formed by arborescent corals (e.g., Anthozoa of the orders Alcyonacea and Antipatharia). The population structure of the habitat-forming corals can inform on the status of the habitat, representing an essential aspect to monitor. Most Mediterranean corals live in the mesophotic and aphotic zones, and their population structures can be assessed by analyzing images collected by underwater vehicles. This is still not possible in whip-like corals, whose colony lengths and flexibilities impede the taking of direct length measurements from images. This study reports on the occurrence of a monospecific forest, of the whip coral Viminella flagellum in the Aeolian Archipelago (Southern Tyrrhenian Sea; 149 m depth), and the assessment of its population structure through an ad-hoc, non-invasive method to estimate a colony height based on its width. The forest of V. flagellum showed a mean density of 19.4 ± 0.2 colonies m⁻² (up to 44.8 colonies m⁻²) and no signs of anthropogenic impacts. The population was dominated by young colonies, with the presence of large adults and active recruitment. The new model proved to be effective for non-invasive monitoring of this near threatened species, representing a needed step towards appropriate conservation actions. Full article

Diterpenoid alkaloids are natural compounds having complex structural features with many stereo-centres originating from the amination of natural tetracyclic diterpenes and produced primarily from plants in the Aconitum, Delphinium, Consolida genera. Corals, Xenia, Okinawan/Clavularia, Alcyonacea (soft corals) and marine sponges are rich sources of diterpenoids, despite the difficulty to access them and the lack of availability. Researchers have long been concerned with the potential beneficial or harmful effects of diterpenoid alkaloids due to their structural complexity, which accounts for their use as pharmaceuticals as well as their lousy reputation as toxic substances. Compounds belonging to this unique and fascinating family of natural products exhibit a broad spectrum of biological activities. Some of these compounds are on the list of clinical drugs, while others act as incredibly potent neurotoxins. Despite numerous attempts to prepare synthetic products, this review only introduces the natural diterpenoid alkaloids, describing ‘compounds’ structures and classifications and their toxicity and bioactivity. The purpose of the review is to highlight some existing relationships between the presence of substituents in the structure of such molecules and their recognised bioactivity. Full article

From the soft coral Xenia umbellata, seven isoprenoid derivatives were isolated, including a new xenicane diterpene, xeniolide O (5) and a new gorgostane derivative gorgst-3β,5α,6β,11α,20(S)-pentol-3-monoacetate (7), along with three known sesquiterpenes (1–3), a known diterpene (4), and a known steroid (6). The extensive analyses of the NMR, IR, and MS spectral data led to determination of their chemical structures. Compounds 1–7 displayed a cytotoxic effect against breast adenocarcinoma (MCF-7), hepatocellular carcinoma (HepG2), and cervix adenocarcinoma (HeLa), with IC₅₀ values ranging between 1.5 ± 0.1–23.2 ± 1.5; 1.8 ± 0.1–30.6 ± 1.1 and 0.9 ± 0.05–12.8 ± 0.5 μg/mL, respectively. Compound 3 showed potent cytotoxic effects against MCF-7, HepG2, and HeLa with IC₅₀ values = 2.4 ± 0.20, 3.1 ± 0.10 and 0.9 ± 0.05 μg/mL, respectively. Compounds 2, 5, and 7 displayed cytotoxic effect against Hela cells with IC₅₀ values = 12.8 ± 0.50, 6.7 ± 1.00 and 11.5 ± 2.20 μg/mL, respectively. Two DNA binding dyes, acridine orange (AO) and ethidium bromide (EtBr) were used for the detection of viable, apoptotic, and necrotic cells. The early apoptotic cell death was observed in all types of treated cells. The late apoptotic cells were highly present in HepG2 cells. Compounds 5 and 7 induced a high percentage of necrosis towards HepG2 and HeLa cells. The late apoptosis was recorded as a high rate after treatment with 7 on all cancer cells. Full article

The pink sea fan Eunicella verrucosa is a habitat-forming octocoral living in the East Atlantic and in the Mediterranean Sea where, under proper circumstances, it can form large populations known as coral forests. Although these coral forests represent vulnerable marine ecosystems of great importance, these habitats are still poorly known, and their monitoring is almost non-existent to date. For this reason, we compared two different models to infer the age of E. verrucosa based on nondestructive measurements of the colonies’ size, in order to highlight strengths and weaknesses of the existing tools for a potential application in long-term monitoring. We also applied the two models on a case-study population recently found in the northwest Mediterranean Sea. Our results showed which model was more reliable from a biological point of view, considering both its structure and the results obtained on the case study. However, this model uses solely the height of the colonies as proxy to infer the age, while the total branch fan surface area could represent a more appropriate biometric parameter to monitor the size and the growth of E. verrucosa. Full article

In this study, we performed a bibliographical review examining the scientific literature on “feeding in Anthozoa” for the period from 1890 to 2019, using the scientific database Google Scholar, supplemented with additional literature. This study categorized published scientific papers on this topic by decade of publication, target taxa, variability of species studied in each order and main themes studied. As a result, 153 studies were found, and based on their content, it was observed that within Anthozoa, there has been a concentration of feeding studies on species in the orders Actiniaria (Hexacorallia), Scleractinia (Hexacorallia), and Alcyonacea (Octocorallia). This indicates that the other remaining orders of the group have been comparatively neglected with regards to their feeding aspects. Therefore, as data on feeding in some groups of Anthozoa are scarce, studies need to be carried out to fill the gaps that permeate this important benthic group, in order to better understand their ecology. Full article

The pink sea fan Eunicella verrucosa (Cnidaria, Anthozoa, Alcyonacea) can form coral forests at mesophotic depths in the Mediterranean Sea. Despite the recognized importance of these habitats, they have been scantly studied and their distribution is mostly unknown. This study reports the new finding of E. verrucosa forests in the Mediterranean Sea, and the updated distribution of this species that has been considered rare in the basin. In particular, one site off Sanremo (Ligurian Sea) was characterized by a monospecific population of E. verrucosa with 2.3 ± 0.2 colonies m⁻². By combining new records, literature, and citizen science data, the species is believed to be widespread in the basin with few or isolated colonies, and 19 E. verrucosa forests were identified. The overall associated community showed how these coral forests are essential for species of conservation interest, as well as for species of high commercial value. For this reason, proper protection and management strategies are necessary. Full article

The Caribbean soft coral Erythropodium caribaeorum is a rich source of erythrolides—chlorinated briarane diterpenoids. These compounds have an ecological role as feeding deterrents, with a wide variation in their composition depending on the location where the sample is collected. In Colombia, this soft coral can be found at different locations in the Caribbean Sea including Santa Marta, Islas del Rosario, and Providencia—three environmentally different coral reef areas in the south and southwest Caribbean Sea. In order to evaluate differences in erythrolide composition, the metabolic profiles of samples from each of these locations were analyzed by HPLC-MS. Principal component analysis showed changes in the diterpene composition according to the sample origin. Diterpenes from samples collected at each location were isolated to describe the three chemotypes. The chemotype from Santa Marta was highly diverse, with the new erythrolides W and X together with eight known erythrolides. The sample from Islas del Rosario showed a low diversity chemotype constituted by high amounts of erythrolide A and B. The chemotype from Providencia showed low chemical diversity with only two main compounds—erythrolide V and R. Evaluation of cytotoxic activity against the human cancer cell lines PC-3, MCF7, and A549 showed erythrolides A and B as the more active compounds with IC₅₀ values in the range from 2.45 to 30 μM. Full article

Alcyonacea (soft corals and gorgonia) are well known for their production of a wide array of unprecedented architecture of bioactive metabolites. This diversity of compounds reported from Alcyonacea confirms its productivity as a source of drug leads and, consequently, indicates requirement of further chemo-biological investigation. This review can be considered a roadmap to investigate the Alcyonacea, particularly those produce nitrogen-containing metabolites. It covers the era from the beginning of marine nitrogen-containing terpenoids isolation from Alcyonacea up to December 2018. One hundred twenty-one compounds with nitrogenous moiety are published from fifteen genera. Their prominent biological activity is evident in their antiproliferative effect, which makes them interesting as potential leads for antitumor agents. For instance, eleutherobin and sarcodictyins are in preclinical or clinical stages. Full article

Previous studies on the chemical constituents of soft corals belonging to the genus Sinularia have led to the isolation of a number of interesting secondary metabolites and some of these were found to possess extensive bioactivities [1–3]. Continuation investigation on the chemical constituents of the marine invertebrates collected off the waters of Taiwan, two new cembrane-type diterpenoids, arbolides A (1) and B (2), and a known steroid, crassarosterol A (3) [4], were isolated from the soft coral Sinularia arborea (family Alcyonacea) (Figure 1). In this paper, we describe the isolation, structure determination and cytotoxicity of compounds 1–3. Full article

A new germacrane-type sesquiterpenoid, menelloide E (1), and a new cembrane-type diterpenoid, lobocrassin F (2), were isolated from the octocorals Menella sp. and Lobophytum crassum, respectively. The structures of terpenoids 1 and 2 were determined by spectroscopic and chemical methods and compound 2 was found to display a significant inhibitory effect on the release of elastase by human neutrophils. Full article