Glutamine synthetase (GS; EC 6.3.1.2; L-glutamate ammonialigase) catalyzes the ATP-dependent conversion of glutamate and ammonia into glutamine. Due to its key role in nitrogen metabolism, including nucleotide, amino acid and urea biosynthesis, the enzyme has been ascribed an extraordinarily long evolutionary history. Thus, GS has been used as a molecular clock to establish phylogenetic relationship between different species. Through the National Center of Biotechnology Information (NCBI) using Basic Local Alignment Search Tool (BLAST) programs BLASTx (translated nucleotide-protein alignment) and BLASTn (nucleotide-nucleotide alignment) system, we obtained the complete cDNA of GS from tilapia cDNA liberary. Furthermore, the results of the alignment of tilapia GS sequence with that of other species indicated a close relationship between tilapia GS and other fishes. We also found that there is 79% homology between mammal and tilapia within the open read frame (ORF) of GS. However, sequence analysis by computer software revealed the fact that the size (0.5 kb) of GS 3¡¦untranslated region (3¡¦-UTR) of tilapia GS is different from that of mammals. Moreover, there is the complete distinct sequence of the 3¡¦-UTR of tilapia GS from that of mammals. The 3'-UTR of many eukaryotic mRNAs has been implicated in the control of mRNA stability, processing, polyadenylation, and translational regulation. Accordingly, to comprehend the role of 3¡¦-UTR in GS phylogenesis, we examine whether the 3'-UTR of tilapia GS is involved in the regulation of GS expression in mammals. We first generated the construct using pEGFP-N2 carrying the ORF (1.1kb) of tilapia GS gene (ORF-GFP) or the full length (1.6kb) of tilapia GS gene (Full-GFP). Transient or stable transfection of C6 gliomal cells with ORF-GFP indicated that GS mRNA and protein was expressed. When C6 cells were stably transfected with Full-GFP, the expression of GS mRNA, but not its protein, was found. Adenine/uridine-rich sequence elements (AREs) of the 3¡¦-UTR have been known to regulate mRNA stability of certain chemokines. Four AREs are also found in the 3¡¦-UTR of tilapia GS. We further generated the constructs with tilapia ORF-GFP and its 3¡¦-UTR containing 1-4 AREs (A1-GFP, A2-GFP, A3-GFP and A4-GFP). Stable transfection of C6 cells with the different constructs indicated that tilapia GS mRNA is normally transcripted, while there was no expression of GS proteins in stable transfectants. The findings suggest tilapia GS protein expression in mammals by its 3¡¦-UTR and unidentified evolutionary role of the 3¡¦-UTR region of GS.

There are two purposes in this research, one is to develop the new method which can be used for detection and quantification of chloramphenicol in fish, and the method is according to Commission Decision 2002/657/EC. The other is to study about the depletion of chloramphenicol in Tilapia which is the main aquacultural product in Taiwan. Homogenized fish tissues were extracted with EtOAc and defatted with Hexane. HPLC separation was conducted on RP18 column in 0.5mM ammonium acetate ¡V MeOH. Chloramphenicol was determinated by LC-ESI-MS-MS in negative mode. The recoveries of chloramphenicol from fish gill, gut, liver and muscle were 68.8, 73.3, 82.7 and 85.5%. The limit of detection was 0.05, 0.14, 0.07 and 0.03 ng/g. Decision limit(CC£\) of fish muscle was 0.05 ng/g and detection capability(CC£]) was 0.07 ng/g. Chloramphenicol was administered by oral and by bathing respectively in Tilapia. Chloramphenicol was given by bathing at 45.8 mg/kg for one hour. No chloramphenicol was demonstrated in gill, gut and fish muscle on 193th hour, 673th hour, and 385th hour respectively after the beginning of this study. There was 0.08 ng/g chloramphenicol in liver after 385th hour. Chloramphenicol was given orally to Tilapia at 354.5 mg/kg daily for 3 days. No chloramphenicol demonstrated in fish muscle on 480th hour. There were 0.09 ng/g and 0.16 ng/g in liver and gut respectively. No matter oral experiment or bathing experiment, th concertration of chloramphenicol in liver is higher than in the other, the depletion rate in high concentration was faster than in low concentration.

The structure and function of brain show sexual dimorphism in vertebrates. Brain sexual differentiation is resulted from the neural development. The neural development of brain is determined by genetic regulation and also influenced by external environmental factors(ex: temperature¡B neurotransmitter ). Serotonin (5-hydroxytrptamine, 5-HT) function as a neurotransmitter and/or neuromodulator in the central nervous system. Serotonin plays a important role in the development of the central nervous system via serotonin receptor¡CAstrocyte has the role of neural supporting and neural protection in CNS. Astrocyte has the important role of brain development. In the present study, the influence of temperature on the proliferation of astrocyte was investigated.These results show that the proliferation of astrocyte are varied with the temperature. Serotonin is not involved in the proliferation of astrocyte .Wherease,but has an effect on the ratio 5-HT+-cell in the astrocyte culture via the 5-HT1A receptor.

No description available.

The goal of this study was to prove that aquaponic systems can produce lettuce of equal growth and quality compared to hydroponic lettuce production and to determine the stocking density of fish required for plant growth. Aquaponics is the integration of recirculating aquaculture and hydroponic plant production. The project had four objectives. The first objective was to determine the biomass of fish required for plant growth to develop a fish to plant density ratio. The second objective was to compare lettuce grown with aquaponic water and a hydroponic solution under the same environmental conditions. The third objective was to compare the quality of lettuce grown with aquaponics water plus nutrient supplementation with a hydroponic solution. The fourth objective was to determine the nitrogen dynamics in the aquaponic system and to compare the nutrient composition of lettuce grown with aquaponics water with nutrient supplementation and hydroponic solution. It was determined that under the specified environmental conditions 5 kg m⁻³ of Nile tilapia (O. niloticus) fed 2% of their body weight daily yields on average 4.7 kg m⁻² of lettuce (L. sativa cv. Rex) in 35 days. There was no significant difference (p ≤ 0.05) in biomass or chlorophyll concentration index in lettuce (L. sativa cv. Rex) grown with aquaponics water and nutrient supplements versus a hydroponic solution. The aquaponics solution generated equal biomass and chlorophyll concentration indexes compared to the hydroponic solution. Aquaponics water plus supplementation can yield L. sativa cv. Rex with equal biomass accumulation and chlorophyll concentration indexes compared to hydroponics lettuce. Nutrients added to the aquaponics system consisted of iron, manganese, and zinc. These nutrient concentrations became depleted in the aquaponics water over time and were not replenished via the fish feed. Dolomite was added to the aquaponics system every two weeks to increase the buffering capacity of the water and maintain optimal pH levels. Aquaponics lettuce had similar nutrient composition to hydroponic lettuce. One head of L. sativa cv. Rex (176.75 ± 31.03) will assimilate approximately 5.96 grams of nitrogen (3.38% per dry gram lettuce). One kilogram of fish will yield 6.4 lettuce heads (1,128 grams) and fixate 38.13 grams of nitrogen.

No description available.

Fermented silage was prepared from a mixture of minced tiiapias (Oreochromis spp. ), different carbohydrate substrates (molasses, corn flour, tapioca flour) and Lactobacillus plantarum as inoculum, incubated anaerobically for 30 days at 5°-35°C. The pH and protein solubilization were temperature-dependent, and the source of carbohydrate substrate did not affect non-protein nitrogen (NPN) content or proximate composition of tilapla silage. During storage at 30°C for 180 days, NPN content increased and there was 8-11% loss of tryptophan. Moist diets containing tilapla silage (stored up to 60 days) were fed to Clarias gariepinus and differences in growth and protein utilization were demonstrated, but there were no effects on body composition. Partial replacement of fish meal with co-dried tilapla silage and soybean flour blend (FSS: BF) in dry diets supported growth and protein utilization similar to the control treatment. Fish growth and protein utilization were reduced with total replacement of fish meal. Apparent protein digestibility decreased with Increasing dietary level of co-dried FSS: BF. Carcass composition was not affected and morphological defects were not observed. Co-dried tilapla silage blended with soybean meal, poultry by-product meal, hydrolysed feather meal or meat and bone meal (FSS: BM, FSP: BM, FSH: FM, FSM: BM) (providing 50% of the dietary protein) In dry diets fed to Oreochromis niloticus and Clarias gariepinus gave differences In growth, protein utilization and digestibility, and apparent energy digestibility. Carcass composition was not affected by silage blend and histological examination of exocrine pancreas, liver and Intestine tissues did not show any lesions suggestive of nutritional imbalance. Haematocrit, haemoglobin content and mean cell haemoglobin concentration values showed no differences among the treatments. The results indicated that fermented tilapla silage is a suitable protein supplement in moist or dry diets for Oreochromis niloticus and Clarias gariepinus, without affecting feed efficiency, fish growth or health.

Nakambala Tilapia Farm commenced operations at the Nakambala Estate of the Zambia Sugar Company near Mazabuka, Zambia in early 1982. The farm used an intensive tank system designed to produce 50 tonnes of tilaplas per annum to provide fish for feeding the labour force on the sugar estate. The project had to manufacture fish feeds on site. A wide range of feed raw materials were used over the course of the project, with formulations designed to aim to supply the nutrient levels suggested by the University of St iIng, Institute of Aquaculture. The raw materials included microalgae from a pilot scale algae culture project funded by the Overseas Development Administration, dried fish, blood meal, carcase meal, soyabeans, cottonseed, hydrolysed feather meal, sunflower oilcake, lucerne, leucaena, yeast, wheatings and maize. Dis involved identification of raw material supplies, development of appropriate feed processing methods, formulation of feeds and manufacture of the feeds. Seventeen feed trials were carried out to evaluatet he use of different feed formulations. Many of these trials concentrated on the supply of vitamins in the feeds as the provision of a vitamin supplement was made impossible by restrictions on foreign exchange allocations. The main conclusions were 1. The poor financial performance of the farm in the initial years of operation was due to problems in project implementation, particularly the absence at the start of the project of a breeding population of tilaplas of a species with proven growth potential in an intensive system. 2. The feeds being produced by 1985 were adequate to sustain good growth in tilapias. Feed trials had shown that there was no need to use a vitamin supplement in the feeds despite advice to the contrary from other authorities. 3. The farming system utilised was appropriate to Zambian conditions, despite being extremely intensive.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 201-220). / Microfiche. / xiii, 220 leaves, bound 29 cm

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1967. / Bibliography: leaves 96-104. / xi, 104 l illus., tables