In the present review, the ongoing researches about selenium research in fish nutrition have been comprehensively discussed. Selenium research is getting popularity in fish nutrition as it is required for the normal growth and proper physiological and biochemical functions in fish. Its deficiency or surplus amounts create severe problems in fish. It is available as inorganic form, organic form, and nano form. In fish, most of the previous research is about the selenium requirements for fish by using only one selenium source mainly the inorganic one. Selenium shows maximum biological activity and bioavailability when it is supplied in proper form. However, to differentiate the more bioavailable and less toxic form of selenium, sufficient information is needed about the comparative bioavailability of different selenium forms in different fish species. In fish, important data about the new forms of selenoproteins is still scarce. Therefore, it is necessary to focus on the determination and elucidation of the new selenoproteins in fish through the utilization of recent approaches of molecular biology and proteomics. The adaptation of these new approaches will replace the old fashioned methodologies regarding the selenium research in fish nutrition. Moreover, the use of molecular biology and proteomics-based new approaches in combination with selenium research will help in optimizing the area of fish nutrition and will improve the feed intake, growth performance, and more importantly the flesh quality which has a promising importance in the consumer market.

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-The purpose of this study was to evaluate behavioral responses and biochemical changes induced by the extensively used pesticide cypermethrin (CYP) in liver, gills, brain and muscle tissues of mahseer (Tor putitora) fry. Behavioral changes in fish after exposure to an acute concentration of CYP involved jumping, abrupt swimming, loss of balance and equilibrium, increased surface activity and air gulping. These changes were more prominent with the passage of time. After a longer period of exposure, the fish became sluggish and before dying occasionally became motionless and sometimes showed a vertical position. Internal hemorrhage was also obvious. CYP exposure resulted in a significant decrease in total protein content in different tissues while antioxidant enzymes, catalase (CAT), peroxidase (POD) and glutathione reductase (GR) showed a time-dependent increasing trend in their activities in liver, brain, gills and muscle tissues. Similarly, lipid peroxidation (LPO) level also increased with time in different tissues of CYP-exposed fish. The results of the present study revealed that CYP is toxic to the mahseer Tor putitora. Therefore, its indiscriminate use can contribute in decreasing the population of mahseer in natural water bodies.

Two new nonionic surfactants; 1-sec-butyl-3-dodecanoylthiourea (DTU) and 1-dodecanoyl-3-phenylthiourea (DPTU) were synthesized and characterized by 1 H NMR, 13 C NMR and FTIR and UV-Vis spectroscopy. The detailed electrochemical fate of DTU and DPTU was investigated in a wide pH range of 2-12 by employing three electroanalytical techniques. The voltammetric signatures of the analytes showed a single irreversible anodic peak followed by two reversible peaks of the oxidation product. The irreversible behavior of the oxidation process was witnessed by the unequal components of total current in square wave voltammetry and scan rate based deviation of peak potential. The involvement of protons accompanying the electron transfer processes was ascertained from peak potential versus pH plots. Critical micelle concentration and hydrophilic-lipophilic balance of the synthesized surfactants were determined for the assessment of their cleaning, wetting and emulsifying properties. Some detergents and surfactants have been restricted and prohibited in the developed countries due to adverse environmental consequences. The manufacturers are now trying to synthesize environmentally friendly surfactants according to the environmental protection laws.1,2 With these facts in mind, we synthesized thiourea based surfactants which are expected to increase the fertility of the soil if their washed water is directed toward agricultural fields.Surfactants are classified as ionics, nonionics and zwitter-ionics. The demand and consumption of ionic surfactants were greater than nonionics in the mid of 19 century but now the market share of nonionic surfactants has reached to 40% of the total worldwide surfactants production. Nonionic surfactants excel other types due to their neutral behavior, compatibility with ionic surfactants and capability of forming complex mixtures as found in many commercial products. 3,4 Nonionic surfactants are used as excellent solubilizing agents due to their very low critical micelle concentration. 5,6 Such surfactants can work even in hard water as they do not yield ions in aqueous solution and hence, less or almost insensitive to electrolytes. Due to their neutral behavior, nonionic surfactants are none or less toxic than ionic surfactants and hence find use in cosmetics, pharmaceuticals and food products.7-9 They can also be used as wetting agents, emulsifiers and detergents.10,11 Nowadays nonionic surfactants are in constant use in different varieties of domestic and industrial products. 12,13 Prompted by the peculiar characteristics of non-ionic surfactants such as very low critical micelle concentration, insensitivity to hard water, no or low toxicity, low cost and compatibility with ionic surfactants, we synthesized and spectroscopically characterized more effective candidates of this class in high yield using the protocol reported in our recent article.14 Moreover, the oxygen, nitrogen and sulfur donor atoms of thiourea derivatives provide a multitude of bonding possibilities. 15 Hence, the excellent me...

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Three novel thiourea‐based non‐ionic surfactants, 3‐decanoyl‐1,1‐diphenylthiourea, 3‐dodecanoyl‐1,1‐diphenylthiourea and 1,1‐diphenyl‐3‐tetradecanoylthiourea were synthesized from carbonyl chlorides, potassium thiocyanate and amines in high yield. The synthesized compounds were characterized by different techniques like 1H NMR, 13C NMR, FTIR and UV‐Visible spectrophotometry. These surfactants are soluble in nonpolar and polar organic solvents and resist solubility in water due to the presence of thiourea group. Electronic absorption spectroscopy was used to evaluate their critical micelle concentration (CMC) in different solvents. The CMC was found to decrease with increase in hydrophobic carbon chain length as expected. Moreover, the effect of pH on their spectral transition was investigated and the two peaks were found to merge in highly alkaline conditions.