Selective release of fatty acids during lipid hydrolysis in frozen-stored milk fish (Chanos chanos)

Lipid hydrolysis and the nature of fatty acids lost as a result of lipid hydrolysis in milk fish (Chanos chanos) during frozen storage at -20°C is discussed in this paper. There was a preferential loss of saturated acids during the first three weeks of storage. This was followed by loss of polyunsaturated acids during the next seven weeks. Sharp decrease in the levels of monounsaturated acids was observed from the 10th week of frozen storage. These observations are due to the preferential hydrolysis of phospholipids with relatively high proportion of saturated acids during the first three weeks, followed by the hydrolysis of phospholipids with high proportions of polyunsaturated fatty acids from the 3rd to the 10th week, and finally, predominant hydrolysis of neutral lipids from the 10th week onwards. Storage of fish in the ice prior to freezing was found to accelerate lipid hydrolysis, especially that of neutral lipids, during frozen storage

Lipid hydrolysis in mackerel (Rastrelliger kanagurta) during frozen storage

The hydrolytic changes in the lipids of mackerel (Rastrelliger kanagurta) during storage at -l8°C were studied with a view to understand the factors involved in the formation of free fatty acids. Only the phosphorylated fraction did undergo hydrolysis at an appreciable rate. It was found that the free fatty acid production was mainly associated with the phospholipid hydrolysis. As regards the triglycerides and unsaponifiable matter, there was no significant change in levels during frozen storage

Lipid breakdown in oil sardine (Sardinella longiceps) during frozen storage

The problem of hydrolysis of lipids and consequent accumulation of free fatty acids and development of rancidity due to oxidation of the lipids are major problems in frozen storage of oil sardine (Sardinella longiceps). The course of the phospholipid breakdown, production of free fatty acids and the changes taking place in the major unsaturated fatty acids during frozen storage are described in this paper. The rate of free fatty acid production is faster in the fish, with the higher fat content. Unlike in lean fish, the neutral lipids are found to contribute substantially to the free fatty acid production. The fatty acids most affected during storage are C sub(20:5) and C sub(22:6). The polyene indices were found to decrease during storage. These effects are more pronounced in the fish with the higher fat content

Studies on lantern fish (Benthosema pterotum) 1. Biochemical and microbiological investigation

Lantern-fish, an under-utilised fish is present in abundance, all the year round in tropical and sub-tropical waters. Biochemical and microbiological studies carried out on lantern fish, caught from the Gulfs of Oman and Aden are reported in this paper

Gonadotropin-Releasing Hormone Agonists Sensitize, and Resensitize, Prostate Cancer Cells to Docetaxel in a p53-Dependent Manner

Gonadotropin-releasing hormone (GnRH) receptors are expressed in prostate cancer, specifically in the most aggressive stage of the tumor (castration-resistant prostate cancer, CRPC) for which the standard treatment, docetaxel-based chemotherapy, can only improve the median survival time by few months. We previously showed that GnRH agonists exert an antitumor activity in CRPC cells; however, a link between GnRH receptors and the apoptotic machinery remains to be defined. Aim of this study was to evaluate whether, in CRPC cells, GnRH agonists might affect the expression/activity of apoptosis-related proteins and might sensitize, or resensitize, cancer cells to chemotherapeutics. We demonstrated that, in p53-positive DU145 cells, GnRH agonists: a) increase the expression of the proapoptotic protein Bax; this effect is mediated by the phosphorylation (activation) of p53, triggered by the p38 MAPK; b) potentiate the antiproliferative/proapoptotic activity of docetaxel; c) resensitize docetaxel-resistant cells to the antitumor activity of the cytotoxic drug. These data indicate that GnRH agonists sensitize and, more importantly, resensitize DU145 CRPC cells to chemotherapy in a p53- dependent manner. To confirm the crucial role of p53 in the activity of GnRH agonists, experiments were performed in p53- null PC3 cells. We found that GnRH agonists fail to increase Bax expression and do not potentiate the cytotoxic activity of docetaxel. These results may provide a rationale for novel combination treatment strategies, especially for docetaxelresistant CRPC patients expressing a functional p53 protein

Thermodynamic studies of AgamOBP4 and AgamOBP5 from Anopheles gambiae with different semiochemicals

Mosquitoes and other arthropods may transmit infectious agents causing several diseases. In such a context, Anopheles gambiae is considered the primary mosquito vector responsible for the transmission of malaria causing more than 1 million deaths each year. The use of repellents is one of the strategies adopted to contrast the spread of such diseases as they reduce the contact frequency between vectors and human targets. Like for other insects, the olfactory system of mosquitoes is essential for finding food, mates and blood meals and Odorant-binding proteins (OBPs) are the first components of their odor detection unit. Specifically, semiochemicals are captured by OBPs after their interaction with insect\u2019s antennae and are delivered to odorant receptors. Therefore, given the crucial role of OBPs, they constitute promising targets for the design of new repellent or attractant molecules and may improve the effectiveness of mosquitos control strategies. Here we present a calorimetric study of the thermodynamic stability of AgamOBP4 and AgamOBP5 and their behaviour against several potential ligands. In spite of the great structural resemblance between these two proteins, nanoDSC investigation performed at different pH values (pH 5.0 and 8.0) revealed different pH-dependent thermodynamic profiles and stability. Moreover, AgamOBP5 and AgamOBP4 exhibited different binding affinities for certain molecules suggesting their ability to recognize different classes of odors and that they are likely involved in different pathways of host recognition. Specifically, among the potential ligands tested, AgamOBP4 preferentially binds to artemisia acetate, whereas AgamOBP5 prefers carvacrol, thymol and cuminaldehyde as binders

Dual targeting of tumor and endothelial cells by Gonadotropin-Releasing Hormone agonists to reduce melanoma angiogenesis

We previously showed that GnRH receptors are expressed in melanoma cells; their activation reduces the cell growth and metastatic behavior. Here, we investigated whether GnRH agonists might affect the expression of genes involved in melanoma progression. By genome wide transcriptomic and by Real Time PCR analysis we first observed that GnRH agonists decrease the expression of the pro-angiogenic factor VEGF (all isoforms) in BLM melanoma cells. Then, we demonstrated that GnRH agonists specifically decrease the expression of the VEGF165 isoform as well as its secretion from BLM cells. These data suggested that activation of GnRH receptors might reduce the pro-angiogenic behavior of melanoma cells. To verify this hypothesis we treated BLM cells with a GnRH agonist; the conditioned medium from these cells was tested to assess its capability to stimulate HUVEC cells motility. The migration of HUVEC cells towards the conditioned medium of GnRH agonist-treated BLM cells was significantly lower than the migration of HUVEC cells towards the conditioned medium of untreated cells. Thus, GnRH agonists reduce the pro-angiogenic behavior of melanoma cells through a decreased production of VEGF. We then found that GnRH receptors are also expressed on HUVEC cells and that GnRH agonists reduce their ability to proliferate and to form capillary-like tubes when stimulated by VEGF. These findings suggest that GnRH agonists exert anti-angiogenic activity indirectly, by decreasing VEGF secretion from tumor cells, and directly, by counteracting the pro-angiogenic activity of the growth factor. These data might lead to the development of novel targeted approaches for melanoma

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Not AvailableOne of the uses of thermally stable dispersions of fish myofibrillar proteins is as edible film. A modified method of preparation of thermostable dispersions was developed which involves acidification of meat water homogenate.The dispersions were cast in glass trays and dried in an oven at 50 degree C. Dried dispersions yielded light yellow translucent films with good flexibility. The films become brittle if dried further or stored at low humidity. Heating the dispersions prior to casting excluded air bubbles and thus improved the quality of films.Not Availabl

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Not AvailablePesticides and polychlorinated biphenyls (PCBs) are ubiquitous toxic constituents due to their bioaccumulation and specific physicochemical properties. These compounds accumulate in the biota of all levels and the residues are present in all environmental compartments from all geographical areas. Elevated pollutant concentrations are generally the consequence of effluent discharge and agricultural and industrial runoffs. Although majority of these compounds enter the environment through anthropogenic activitiesa, marine algae and invertebrates and natural processes such as forest fire also contribute their share. The development of global quality assurance criteria and the general awareness of the consumer for quality of the food forced a new approach in the quality aspects of food commodities and seafood is no exception to this. In the light of strigent safety measures with respect to seafood imposed by EU and other developed countries, the understanding on pesticides and PCBs assumes significance. Though present in extremely low concentrations, they definitely pose a chronic health hazard. However, the major problem, associated with these chemicals was their method of detection . The advancement of gas chromatographic and HPLC systems has made it possible to quantify these toxic chemicals for the benefit of the mankind. This paper provides an insight into the general aspects of pesticides and PCBs besides highlighting the health hazards, bioaccumulation in sediments, fish and other aquatic biota and their relevance to the quality assurance system of seafood.Not Availabl