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Polychaetes play a prominent role in marine systems, but little is known about their secondary metabolites compared with other benthic taxa. In the present study, we investigated the toxicity of hallachrome, an unusual 1-2 anthraquinone identified from the skin of some polychaetes, including the Mediterranean infaunal species Halla parthenopeia. Under stress conditions, this worm releases a harmful purple mucus, whose noxious compounds were still unknown. We hypothesized that hallachrome also occurs in the purple mucus, giving rise to its color and toxicity. Soon after the production of the purple exudate, H. parthenopeia also secretes a harmless, transparent mucus, which pushes away the toxic one, suggesting protective functions for the worm itself. LC-MS and 1H-NMR analyses confirmed the presence of the pigment hallachrome in the purple mucus. The average concentration of the pigment in the purple mucus was about 310 mg L-1. Ecotoxicological bioassays on representative species of bacteria, protozoans, rotifers, crustaceans (Artemia franciscana) and polychaetes (Dinophilus gyrociliatus) revealed its severe toxic effects: LC50/EC50 values ranged from 0.11-5.67 mg L-1. Hallachrome showed higher toxicity for A. franciscana than other naturally occurring anthraquinones. Tests on encapsulated embryos of D. gyrociliatus evidenced the ability of a mucus layer to limit hallachrome diffusion, confirming the protective role of the transparent mucus. Given the information available on polychaetes anti-predator strategies, hallachrome cannot be considered a consumer deterrent. However its toxicity and wide range of activity suggest chemical defensive functions against potential competitors, parasites and/or pathogens. [ABSTRACT FROM AUTHOR]

We have examined the morphological and functional characteristics of the celomic cells in the marine fireworm Hermodice carunculata. The cells differ in morphology, in relation to the presence of cytoplasmic granules, adhere to the glass, phagocytize zymosan A particles and contain ACTH-like molecules. We suggest the presence of only one cell type in the worm celomic fluid, i.e., the immunocyte described in other invertebrates. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is a critical global health issue, with rising resistance among bacteria and fungi. Marine organisms have emerged as promising, but underexplored, sources of new antimicrobial agents. Among them, marine polychaetes, such as Halla parthenopeia , which possess chemical defenses, could attract significant research interest. This study explores the antimicrobial properties of hallachrome, a unique anthraquinone found in the purple mucus of H. parthenopeia , against Gram-negative bacteria ( Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027), Gram-positive bacteria ( Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228), and the most common human fungal pathogen Candida albicans ATCC 10231. Antibacterial susceptibility testing revealed that Gram-negative bacteria were not inhibited by hallachrome at concentrations ≤2 mM. However, Gram-positive bacteria showed significant growth inhibition at 0.12-0.25 mM, while C. albicans was inhibited at 0.06 mM. Time-kill studies demonstrated dose-dependent growth inhibition of susceptible strains by hallachrome, which exerted its effect by altering the membrane permeability of C. albicans , E. faecalis , and S. epidermidis after 6 h and S. aureus after 24 h. Additionally, hallachrome significantly reduced biofilm formation and mature biofilm in S. aureus , E. faecalis , and C. albicans . Additionally, it inhibited hyphal growth in C. albicans . These findings highlight hallachrome's potential as a novel antimicrobial agent, deserving further exploration for clinical experimentation.

We aimed to demonstrate the applicability of Snyder's arthroscopic classification of rotator cuff tears (RCT) in shoulder ultrasound (US) and to compare it with MR arthrography (MRA). Forty-six patients (34 males; mean age:34 ± 14 years) underwent shoulder US and MRA. Two radiologists (R1 = 25 years of experience; R2 = 2 years of experience) assigned A1-4, B1-4, or C1-4 values depending on the extent of RCT in both US and MRA. Inter-reader intra-modality and intra-reader inter-modality agreement were calculated using Cohen's kappa coefficient. US sensitivity and specificity of both readers were calculated using MRA as the gold standard. Patients were divided into intact cuff vs. tears, mild (A1/B1) vs. moderate (A2-3/B2-3) tears, mild-moderate (A2/B2) vs. high-moderate (A3/B3) cuff tears, moderate (A2-3/B2-3) vs. advanced (A4/B4) and full-thickness (C) tears. The highest agreement values in inter-reader US evaluation were observed for mild-moderate vs. high-moderate RCT (K = 0.745), in inter-reader MRA evaluation for mild vs. moderate RCT (K = 0.821), in R1 inter-modality (US-MRA) for mild-moderate vs. high-moderate and moderate vs. advanced/full-thickness RCT (K = 1.000), in R2 inter-modality (US-MRA) for moderate vs. advanced/full-thickness RCT (K = 1.000). US sensitivity ranged from 88.89%(R1)-84.62%(R2) to 100% (both readers), while specificity from 77.78%(R1)-90.00%(R2) to 100% (both readers). Snyder's classification can be used in US to ensure the correct detection and characterization of RCT.

Increasing evidence in the field of bioprospection fosters the necessity of studying poorly investigated poisonous marine invertebrates to expand knowledge on animal venom biology. Among marine annelids, amphinomid fireworms are notorious for their bearded trunk equipped with a powerful stinging capacity. Here, a methodological workflow based on analytical chemistry techniques (compound isolation followed by mass spectrometry and spectroscopy analyses) was applied to gain new insights, leading to the identification and structural elucidation of an array of natural products from Mediterranean specimens of Hermodice carunculata . Eight betaine-derived unprecedented compounds, named "carunculines", were detected, bearing two terminal ammonium groups tri-and disubstituted at the Cα (A, B) and a series of different alkyl chains (I-VIII). The mixture of chemicals was found in all the body parts of H. carunculata , supporting a mechanism of action triggered by their vehiculation inside the dorsal chaetae, and subsequent injection when chaetae break off on contact. Preliminary investigations to understand adaptive features were also performed, showing a trend in carunculine abundance that fits into the evolutionary history of these worms. These findings shed light on the chemical ecology of amphinomids, giving reasons for the success of H. carunculata in benthic environments and providing promising novel metabolites for biotechnological implications., Competing Interests: The authors declare that they have no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

(1) Background: Despite progression in surgical techniques and immunological treatments, hepatic artery (HA) thrombosis and stenosis still develop as an early or late liver transplant (LT) complication. We aimed to compare superb microvascular imaging (SMI) with conventional Doppler imaging (CDI) in the assessment of HA in a cohort of pediatric patients undergoing follow-up ultrasound (US) for LT. (2) Methods: This prospective, observational study included 73 pediatric LT recipients (median age, 7 years; IQR, 5.8 years; 35 females) who underwent US during LT follow-up from March to December 2019. For each examination, CDI and SMI were separately assessed in terms of HA visibility and spectral waveform morphology (SWM). The former was scored based on HA discrimination from the blooming signal of the surrounding vessels, as follows: 0, not visible; 1, majority course hardly distinguishable; and 2, majority course clearly distinguishable. The latter was scored on a two-point scale: 0, combined venous and arterial SWM, and 1, pure arterial SWM. The patient's overall score was finally calculated by adding the two individual scores. (3) Results: Both the absolute scores and frequency of overall scores equal to 3 (maximum global score) were higher using SMI compared with CDI. The median overall score was 3 for SMI and 2 for CDI ( p = 0.011; IQR = 1). An overall score equal to 3 was obtained in 74% and 49.3% of the study population using SMI and CDI, respectively ( p = 0.002). This was attributable to a better score in HA visibility ( p = 0.007). (4) Conclusions: SMI has shown promise for assessing HA in pediatric LT recipients, possibly serving as a complementary non-invasive tool of CDI in everyday practice.

The spreading of alien and invasive species poses new challenges for the ecosystem services, the sustainable production of food, and human well-being. Unveiling and targeting the immune system of invasive species can prove helpful for basic and applied research. Here, we present evidence that a nematode ( Phasmarhabditis hermaphrodita )-based molluscicide exerts dose-dependent lethal effects on the golden apple snail, Pomacea canaliculata . When used at 1.7 g/L, this biopesticide kills about 30% of snails within one week and promotes a change in the expression of Pc-bpi , an orthologue of mammalian bactericidal/permeability increasing protein (BPI). Changes in Pc-bpi expression, as monitored by quantitative PCR (qPCR), occurred in two immune-related organs, namely the anterior kidney and the gills, after exposure at 18 and 25 °C, respectively. Histological analyses revealed the presence of the nematode in the snail anterior kidney and the gills at both 18 and 25 °C. The mantle and the central nervous system had a stable Pc-bpi expression and seemed not affected by the nematodes. Fluorescence in situ hybridization (FISH) experiments demonstrated the expression of Pc-bpi in circulating hemocytes, nurturing the possibility that increased Pc-bpi expression in the anterior kidney and gills may be due to the hemocytes patrolling the organs. While suggesting that P. hermaphrodita -based biopesticides enable the sustainable control of P. canaliculata spread, our experiments also unveiled an organ-specific and temperature-dependent response in the snails exposed to the nematodes. Overall, our data indicate that, after exposure to a pathogen, the snail P. canaliculata can mount a complex, multi-organ innate immune response.

Maternal temperature is known to affect many aspects of offspring phenotype, but its effect on offspring physiological thermal tolerance has received less attention, despite the importance of physiological traits in defining organismal ability to cope with temperature changes. To fill this gap, we used the marine polychaete Ophryotrocha labronica to investigate the influence of maternal temperature on offspring upper and lower thermal tolerance limits, and assess whether maternal influence changed according to the stage of offspring pre-zygotic development at which a thermal cue was provided. Measurements were taken on adult offspring acclimated to 18 or 30°C, produced by mothers previously reared at 24°C and then exposed to 18 or 30°C at an early and late stage of oogenesis. When the shift from 24°C was provided early during oogenesis, mothers produced offspring with greater cold and heat tolerance whenever mother-offspring temperatures did not match, with respect to when they matched, suggesting the presence of an anticipatory maternal effect triggered by the thermal variation. Conversely, when the cue was provided later during oogenesis, more tolerant offspring were observed when temperatures persisted across generations. In this case, maternal exposure to 18 or 30°C may have benefited offspring performance, while limitations in the transmission of the thermal cue may account for the lack of correlation between maternal experiences and offspring performance when mother-offspring environments did not match. Our results provided evidence for a trans-generational effect of temperature on physiological performance characterised by a high context dependency, and are discussed in the light of maternal pre-reproductive experiences., (© 2014. Published by The Company of Biologists Ltd.)

The recent ban on TBT in boat antifouling paints has resulted in a large employment of the biocide zinc pyrithione (ZnPT) as substitute. Despite concerns of its environmental toxicity at ultra-trace concentrations, ZnPT has received little attention, as it was assumed to photo-degrade easily. However, recent evidence has suggested that ZnPT degrades only partially, and persists in the marine environment, especially where the influence of light is limited, such as in harbours. Short-term acute toxicity tests and life table response experiments (LTREs) were performed to evaluate the effects of ZnPT on the polychaete Dinophilus gyrociliatus at both individual and population level. The 96h-LC(50) values for ZnPT on D. gyrociliatus were 7.8 and 11.5nM under dark and 12h light/12h dark conditions, respectively. In LTREs, laboratory cultured cohorts of D. gyrociliatus were exposed to sublethal concentrations of ZnPT (0.5 and 1nM) and compared to a control cohort. The survival among individuals exposed to the highest concentration decreased already during the 2nd week of life with respect to the control. The effects of the biocide on fecundity were even more evident: ZnPT caused a considerable reduction in both the exposed groups. The demographic approach applied here succeeded in identifying ZnPT effects both on the biological cycle and on the growth potential of polychaete D. gyrociliatus. The net growth rate (R(0)) appeared to be the demographic parameter most sensitive to ZnPT, as the biocide exposure was associated with a sharp decline of R(0) in both the 0.5 and the 1nM groups (-41% and -63%, respectively) in comparison to the control cohort. The population growth rate lambda (often used as an index of population fitness) and the life expectancy e(0) were also significantly reduced, while ZnPT exposure did not affect the generation time T. These results highlight the potential ecological threat posed by the biocide ZnPT, even at the very low tested concentrations, which are already detectable in some European marinas.

1. The relationships between life history, fitness and sexuality, together with their ecological and evolutionary significance, has been analysed comparing the main life-history traits and demography in three closely related species belonging to the genus Ophryotrocha. The species are: the gonochoristic O. labronica, the simultaneous hermaphrodite O. diadema and the protandrous hermaphrodite O. puerilis. 2. Survivorship and reproductive data were collected weekly and were used to construct life tables and population projection matrices for each species and compare life-history characteristics. Elasticity, life-table response and decomposition analyses were performed to examine the relative contribution of fecundity and survivorship to differences in lamda between species. 3. The gonochoristic and hermaphroditic species differ in all the main life-history parameters and also in demographic characteristics. In particular the value of lamda, used commonly to express fitness, is markedly higher in the gonochoristic species while in terms of fitness simultaneous and sequential hermaphroditism are very similar. In the genus Ophryotrocha gonochorism currently represents the most widespread condition, being characteristic of the majority of the known species in the genus. 4. Given the demographic advantage ensured by gonochorism, it remains be understood why some species have retained simultaneous hermaphroditism and one has evolved a sequential type hermaphroditism; the most probable hypothesis is correlated with the density of the species in natural habitats.

A life-table response experiment (LTRE) was performed in order to study the effects of enhanced zinc on the survival, fecundity and demographic indices of Dinophilus gyrociliatus (Polychaeta). A control group and three treated cohorts kept in artificial seawater enriched with nominal concentrations of zinc at 0.25, 0.50 and 1.00 microg Zn/ml, respectively, were considered. Zinc marginally affected survival but had a strong impact on the reproduction of D. gyrociliatus. Zinc enrichment had no effect on age at maturity, whereas it induced a slight increase in fecundity during the early reproductive phases at 0.50 and 1.00 microg Zn/ml, and a sharp decrease in fecundity from the 20th day of life at all levels of metal enrichment tested. Treated groups were characterised by a marked reduction of the net growth rate (R0) and a decrease in generation time (T) with respect to the control groups, but no effect on life expectancy (e0) or on population growth rates (lambda) was observed. R0 and lambda, which are the most commonly used indices of fitness, were not equally susceptible to zinc. Lambda appears less sensitive to stress induced by metal enrichment with respect to R0 and other life history traits like age-specific fecundity. D. gyrociliatus appears to be an appropriate bioindicator species in LTRE to assess the consequences of environmental heavy metals on individual life-history and population dynamics.