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The effect of temperature and substrates on polyp settlement of the spotted tellyfish, phyllorhiza punctata (Von Lendenfeld, 1884)

Publication . Pinto, Carlos Daniel Carvalho; Marques, Sónia Cristina Ferreira Cotrim; Leandro, Sérgio Miguel Franco Martins

In recent decades, human activity has been known to influence Earth’s marine ecosystems in a multitude of different ways, such as through global warming, overfishing, coastal or marine construction, pollution, among others. These impacts will then produce different effects on the affected organism populations. One of these groups is the gelatinous one, which has gained a lot of scientific interest due to the increased frequency and abundance jellyfish populations worldwide. It is speculated that human activities may have an impact on the development and reproduction of these species. Therefore, the aim of this work was to evaluate the effect of temperature, and different substrates on the asexual reproduction and polyp settlement of the jellyfish species Phyllorhiza punctata (Von Lendenfeld, 1884). Polyps of P. punctata were subjected to two different experiments. In the first experiment, the polyps were exposed to four different temperatures (22, 24, 26, and 28 ºC), and provided with five different substrate types (glass, rock, shell, plastic (PVC), and fishing net). After 60 days, the total number of polyps for each substrate and temperature was observed. In the second experiment, a different group of polyps was exposed to the same five substrates at the temperature of 24 ºC, and after 60 days, the total number of polyps, and their preferred distribution were compared. The results showed significant differences between the temperatures of 22 and 26 ºC, showing that higher temperatures have a positive effect on polyp asexual reproduction. It was also verified that a lower number of polyps was obtained at 28 ºC when compared with to 26 ºC, which indicates that this temperature may be outside the optimal range for P. punctata polyps, and therefore might restrict polyp reproduction instead. This leads us to believe that slight warming may benefit polyp asexual reproduction of P. punctata, but only within the limits supported by the species. Furthermore, polyp settlement occurred in all the provided substrates, although significant differences were observed between the plastic and the glass, rock, and shell substrates, being the later three significantly preferred over the first one. It was also possible to perceive a higher preference by the polyps to positions further away from the bottom of the goblet (negative geotaxis). In conclusion, marine-bound human activities appear to influence gelatinous organisms, and as such, further studies are required to better understand their influence on these organisms.

2021-07-28Master thesis

Open access

Homarus gammarus (Crustacea: Decapoda) larvae under an ocean acidification scenario: responses across different levels of biological organization

Publication . Rato, Lénia D.; Novais, Sara C.; Lemos, Marco F.L.; Alves, Luís M.; Leandro, Sérgio M.

The present study evaluated the effects of exposure to different target pCO2 levels: control (C: 370 μatm, pH =8.15) and ocean acidification (OA: 710 μatm, pH=7.85) on development and biochemical responses related with oxidative stress and energy metabolism during the crustacean Homarus gammarus (L.) larval development, integrating different levels of biological organization. After hatching in the laboratory, larvae from the same female brood were exposed to the described conditions from hatching until reaching Stage III (last larval stage - 11 days). H. gammarus larvae demonstrated some susceptibility when addressing the predicted pCO2 levels for 2100. Further analysis at the biochemical and physiological level highlighted the occurrence of oxidative stress in the OA scenario (Superoxide Dismutase reduction and higher DNA damage) that was followed by developmental effects, increased inter-moult period from SII to SIII and reduced growth. The extended exposure to these conditions may affect organisms' key life-cycle functions such as physiological resistance, growth, sexual maturation, or reproduction with implications in their future fitness and population dynamics.

2017Journal article

Restricted access

Analysis of Pelagia noctiluca proteome reveals a red fluorescent protein, a zinc Metalloproteinase and a Peroxiredoxin

Publication . Frazão, Bárbara; Campos, Alexandre; Osório, Hugo; Thomas, Benjamin; Leandro, Sérgio; Teixeira, Alexandre; Vasconcelos, Vitor; Antunes, Agostinho

Pelagia noctiluca is the most venomous jellyfish in the Mediterranean Sea where it forms dense blooms. Although there is several published research on this species, until now none of the works has been focused on a complete protein profile of the all body constituents of this organism. Here, we have performed a detailed proteomics characterization of the major protein components expressed by P. noctiluca. With that aim, we have considered the study of jellyfish proteins involved in defense, body constituents and metabolism, and furthered explore the significance and potential application of such bioactive molecules. P. noctiluca body proteins were separated by1D SDS–PAGE and 2DE followed by characterization by nanoLC-MS/MS and MALDI-TOF/TOF techniques.Altogether, both methods revealed 68 different proteins, including a Zinc Metalloproteinase, a Red Fluorescent Protein (RFP) and a Peroxiredoxin. These three proteins were identified for the first time in P. noctiluca. Zinc Metalloproteinase was previously reported in the venom of other jellyfish species. Besides the proteins described above, the other 65 proteins found in P. noctiluca body content were identified and associated with its clinical significance. Among all the proteins identified in this work we highlight: Zinc metalloproteinase, which has a ShK toxin domain and therefore should be implicated in the sting toxicity of P. noctiluca.; the RFP which are a very important family of proteins due to its possible application as molecular markers; and last but not least the discovery of a Peroxiredoxin in this organism makes it a new natural resource of antioxidant and anti-UV radiation agents.

2017Journal article

Restricted access