A pyridinium derivative from Red Sea soft corals inhibited voltage-activated potassium conductances and increased excitability of rat cultured sensory neurones

BACKGROUND: Whole cell patch clamp recording and intracellular Ca(2+ )imaging were carried out on rat cultured dorsal root ganglion (DRG) neurones to characterize the actions of crude extracts and purified samples from Red Sea soft corals. The aim of the project was to identify compounds that would alter the excitability of DRG neurones. RESULTS: Crude extracts of Sarcophyton glaucum and Lobophyton crassum attenuated spike frequency adaptation causing DRG neurones to switch from firing single action potentials to multiple firing. The increase in excitability was associated with enhanced KCl-evoked Ca(2+ )influx. The mechanism of action of the natural products in the samples from the soft corals involved inhibition of voltage-activated K(+ )currents. An active component of the crude marine samples was identified as 3-carboxy-1-methyl pyridinium (trigonelline). Application of synthetic 3-carboxy-1-methyl pyridinium at high concentration (0.1 mM) also induced multiple firing and reduced voltage-activated K(+ )current. The changes in excitability of DRG neurones induced by 3-carboxy-1-methyl pyridinium suggest that this compound contributes to the bioactivity produced by the crude extracts from two soft corals. CONCLUSION: Sarcophyton glaucum and Lobophyton crassum contain natural products including 3-carboxy-1-methyl pyridinium that increase the excitability of DRG neurones. We speculate that in addition to developmental control and osmoregulation these compounds may contribute to chemical defenses

Fisheries and biodiversity along Mediterranean Sea: Italian and Egyptian coast overview

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temperature changes and marine fish species epinephelus coioides and sparus aurata role of oxidative stress biomarkers in toxicological food studies

The increase of seawater temperature as a result of global climate variation elucidates a major challenge for marine organisms survival in addition to consumers safety. Spotted grouper (Epinephelus coioides) and Seabream (Sparus aurata) were collected in water with different temperature variations at Suez Canal and Alexandria (Suez and Abu Qir bay) in Egypt with the aim to assess expression levels of heat shock proteins such as HSP47, HSP70 and HSP90 genes in addition to antioxidants value through enzymes activity: Glutathione-S-Transferase (GST) and Glutathione Peroxidase (GPx). Research results revealed that expression of the HSP47, HSP70a and HSP90 genes increased in marine fishes tissues collected from Suez Canal, with higher water temperature (23:28ºC), compared with those collected from Alexandria (19:24°C) whereas the content of GPx and GST decreased. Our results show alteration of the marker examined suggesting that the increase of heat shock protein genes expression levels of fish collected from Suez Canal might be exposed mainly to thermal oxidative stress response more than those collect from Alexandria. The increase of heat shock protein-related genes expression could be considered as a factor in prohibiting the heat shock transcription factor that may lead to stimulation of heat-inducible genes in addition to heat acclimation. Thus, warming of water is also likely to alter the composition and abundance of food resources, e.g. fish muscles, available to higher trophic level consumers

First record of Percnon gibbesi (H. Milne Edwards, 1853) (Crustacea: Decapoda: Percnidae) from Egyptian waters

3 pages, 2 figuresOn July 2010, the invasive crab Percnon gibbesi was photographed and captured along the coast of Alexandria (Egypt, Eastern Mediterranean Sea). This represents the first observation of this species in Egyptian waters and the easternmost record for the southern rim of the MediterraneanWe acknowledge the Euromediterranean Center for Climatic Changes and the Italian Ministry for the Environment and the Territory (Project: The impacts of biological invasions and climate change on the biodiversity of the Mediterranean Sea). The suggestions of two anonymous referees improved the quality of this paperPeer reviewe

The prevention impact of the green algal extract against genetic toxicity and antioxidant enzyme alteration in the Mozambique tilapia

Algal studies are primary for ecological risk assessment and toxicology by evaluating lethal and sub-lethal toxic impacts of potential toxicants on inhabitants of numerous ecosystems. Dunaliella salina, a green marine alga, is characterized by its carotenoid accumulation and is widely used in many health and nutritional products. Our experiment was designed to evaluate algal extract's ability to inhibit genetic alterations induced by mutagen agents such as dioxin in the Mozambique tilapia. The expression of three stress genes was examined: heat shock protein 90 (Hsp90), CYP1A1 as one of the main cytochrome P450 enzymes, and metallothionein (MT). The study exhibited a characteristic sensitivity to metal treatments. Liver samples were collected from all fish to analyze bio-indicators, including superoxide dismutase (SOD), malondialdehyde (MDA), and reactive oxygen species (ROS). While gills samples were used for DNA fragmentation assay. Results showed that oxidative stress in the dioxin group's liver significantly changed indicators. However, the dioxin group significantly increased the SOD, MDA enzyme activities, and ROS formation. Interestingly, the genes Hsp90, CYP1A1, and MT expression were significantly down-regulated in Dunaliella salina groups. Nevertheless, DNA fragmentation in gill organs was affected by exposure to dioxin in fish. Thus, it was concluded that the methanolic extract of an isolated strain Dunaliella salina is effective against mutagen agent dioxin by inhibiting genetic alterations in fish organs with an antioxidant defense system to conquer oxidative damage

Climate Change and Reproductive Biocomplexity in Fishes: Innovative Management Approaches towards Sustainability of Fisheries and Aquaculture

The ongoing rapid climate change, combined with the disturbance of fish breeding grounds, may impact reproduction by endangering successful breeding and survival, and thus affect the viable sustainability in aquaculture systems as well as in the sea. In this study we focus on the biocomplexity of fish reproduction in response to climate change. Further, we propose adaptive strategies, including technological advancements, using a noninvasive and non-lethal approach, and we outline an assisted reproduction and nutrigenomics approach to mitigating fish reproductive risks posed by climate change. This was done in an effort to monitor fish aquaculture and ensure that, as a livelihood, it may provide a useful source of nutrition for our society

The duckweed, Lemna minor modulates heavy metal-induced oxidative stress in the Nile tilapia, Oreochromis niloticus

A two-fold integrated research study was conducted; firstly, to understand effects of copper (Cu) and zinc (Zn) on the growth and oxidative stress in Nile tilapia, Oreochromis niloticus; secondly, to study the beneficial effects of the duckweed Lemna minor L. as a heavy metal remover from wastewater. Experiments were conducted in mesocosms with and without duckweed. Tilapia fingerlings were exposed to Cu (0.004 and 0.02 mg L-1) and Zn (0.5 and 1.5 mg L-1) and fish fed for four weeks. We evaluated the fish growth performance, the hepatic DNA structure using comet assay, the expression of antioxidative genes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx and glutathione-S-transferase, GST) and GPx and GST enzymatic activity. The results showed that Zn exhibited more pronounced toxic effects than Cu. Low dose of Cu did not influence the growth whereas higher doses of Cu and Zn significantly reduced the growth rate of tilapia compared to control, but addition of duckweed prevented weight loss. Further, in the presence of a high dose of Cu and Zn, DNA damage decreased, antioxidant gene expressions and enzymatic activities increased. In conclusion, results suggest that duckweed and Nile tilapia can be suitable candidates in metal remediation wastewater assessment programs