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Culture Units (culture + unit)

Distribution by Scientific Domains

Earth and Environmental Science	66%

Selected Abstracts

Lecithin requirements of juvenile Australian red claw crayfish Cherax quadricarinatus

AQUACULTURE NUTRITION, Issue 4 2003
K.R. Thompson
Abstract Australian red claw crayfish Cherax quadricarinatus is considered a popular crustacean species in several countries around the world because of its large size potential and resemblance to high-priced American lobsters. However, little is currently known of the nutrient requirements and practical diet formulations for red claw. Lecithin has been shown to be required in the diets of several crustacean species, but there are no reports of dietary lecithin requirements for red claw. A 10-week feeding trial was conducted in an effort to evaluate lecithin requirements for juvenile red claw. Juvenile red claw (mean individual weight of 1.6 ± 0.91 g) were individually stocked in a recirculating system at random into 80 plastic-mesh culture units, each containing its own individual water line. There were 20 red claw per treatment (diet). Water was recirculated through biological and mechanical filters. Four semi-purified diets were formulated to contain increasing percentages of commercial soya bean lecithin (0, 0.5, 1.0 and 2.0%). Diet ingredients included solvent-extracted menhaden fish meal (FM), casein, dextrin, wheat flour, pellet binder, vitamin and mineral mix, cod liver oil, and corn oil. Semi-purified diets were formulated to contain 40% protein using casein, menhaden FM, and wheat flour as protein sources. After 10 weeks, no significant differences (P > 0.05) were found in final weight, percentage weight gain and specific growth rate with average values of 13.0 g, 934%, and 3.14% day,1, respectively. Percentage survival was high during the 10-week period (100, 95, 100 and 95%) as only two individuals died during the study; one of these, because of an escape from the culture unit. There was also no significant differences (P > 0.05) in percentage moisture, protein, fat and ash in whole-body red claw carcasses (wet-weight basis) among any treatment (diet) and averaged 77.1, 12.6, 1.3 and 6.2%, respectively. Based upon the present study, these results indicate that a diet containing 5% cod liver oil and 1% corn oil, and having no supplemental lecithin, may be sufficient for growth and survival of juvenile red claw crayfish. [source]

Microfluidic Tissue Model for Live Cell Screening

BIOTECHNOLOGY PROGRESS, Issue 4 2007
Philip J. Lee
We have developed a microfluidic platform modeled after the physiologic microcirculation for multiplexed tissue-like culture and high-throughput analysis. Each microfabricated culture unit consisted of three functional components: a 50 ,m wide cell culture pocket, an artificial endothelial barrier with 2 ,m pores, and a nutrient transport channel. This configuration enabled a high density of cancer cells to be maintained for over 1 week in a solid tumor-like morphology when fed with continuous flow. The microfluidic chip contained 16 parallel units for "flow cell" based experiments where live cells were exposed to a soluble factor and analyzed via fluorescence microscopy or flow-through biochemistry. Each fluidically independent tissue unit contained ,500 cells fed with a continuous flow of 10 nL/min. As a demonstration, the toxicity profile of the anti-cancer drug paclitaxel was collected on HeLa cells cultured in the microfluidic format and compared with a 384-well dish for up to 5 days of continuous drug exposure. [source]

Comparison of Three Culture Methods for the Intensive Culture of Northern Quahog Seed, Mercenaria mercenaria

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2001
Timothy J. Pfeiffer
A number of approaches have been utilized for growing bivalve hatchery seed (1 mm) to a size suitable for field planting (< 8 mm) but few have been directly compared. This study evaluated the growth and survival of northern quahog seed in three different culture systems and two different stocking densities. The three systems were: 1) a stacked-tray unit with downward water flow; 2) traditional upweller culture units with water flowing upward without seed bed expansion; and 3) upweller culture units with water flowing upward at fluidization velocities to provide seed bed expansion. The two stocking densities were 1.0 and 3.0 g whole wet weight clam/cm2 respectively. During each trial period the seed clams were fed a 1% daily ration (% dry weight algae per wet weight clam per day) of the cultured diatom Chaetoceros muelleri. After 14 d of culture at the 1.0 g whole wet weight/cm2 stocking density, seed clams (4.4 ± 0.6 mm initial shell length) under fluidized-flow condition exhibited better growth (0.54/d), and a greater final shell length (5.9 ± 1.0 mm). At the high density stocking conditions, after 28 d of culture, seed clams (4.2 ± 0.6 mm initial shell length) in the fluidized-flow culture conditions again exhibited better growth rate (0.031/d) and a greater final shell length (6.0 ± 1.0 mm). The preliminary evaluation of fluidized-flow for seed clam culture in land-based nurseries indicates its potential as a suitable alternative to raceway, downwelling, or traditional forced-flow culture methods. [source]

Lecithin requirements of juvenile Australian red claw crayfish Cherax quadricarinatus

Effects of in vitro exposure to ozone and/or hyperoxia on superoxide dismutase, catalase, glutathione and lipid peroxidation in red blood cells and plasma of rainbow trout, Oncorhynchus mykiss (Walbaum)

AQUACULTURE RESEARCH, Issue 3 2002
O Ritola
Abstract In aquaculture, ozone is used as a disinfectant. In its production, extensive amounts of oxygen are formed resulting in hyperoxic conditions in culture units. Both ozone and hyperoxia have the potential to be toxic via pro-oxidant mechanisms and to activate antioxidant defence systems in cultured species. To eliminate systemic effects, blood of rainbow trout, Oncorhynchus mykiss (Walbaum), was exposed in vitro for 5 min to ozone/hyperoxia or hyperoxia, and changes in antioxidant defences and lipid peroxidation were measured after exposure. Ozone exposure caused severe damage in red blood cells (rbc) detected as increased lipid peroxidation and oxidized glutathione (GSSG) levels in both plasma and rbc. Oxygen exposure alone increased intracellular lipid peroxidation and GSSG levels 10 min after exposure and was not evident in the plasma at any time. Ozone, but not oxygen exposure, decreased reduced glutathione (GSH) levels in plasma, and the changes were negatively correlated with increased lipid peroxidation in rbc, indicating that extracellular GSH has a dynamic role in the protection of rbc from direct oxidation by ozone. Both ozone and hyperoxic conditions increased superoxide dismutase (SOD) activity in rbc 3 and 6 h after exposure. In contrast, catalase activity was only increased 10 min after oxygen exposure, suggesting other catalase activation mechanisms rather than enzyme induction. The recovery of lipid peroxidation and GSSG levels in rbc after hyperoxia, but not ozone exposure, indicated a capacity to defend against hyperoxia-produced oxidative damage, but an overwhelming of antioxidant defences by ozone in rainbow trout rbc in vitro. [source]

Osteogenic Evaluation of Glutaraldehyde Crosslinked Gelatin Composite with Fetal Rat Calvarial Culture Model

ARTIFICIAL ORGANS, Issue 8 2001
Hwa-Chang Liu
Abstract: The cytotoxicity of the synthetic bone substitute composed of tricalcium phosphate and glutaraldehyde crosslinked gelatin (GTG) were evaluated by osteoblast cell culture. In a previous study, the GTG composites were soaked in distilled water for 1, 2, 4, 7, 14, 28, and 42 days, and then the solutions (or extracts) were cocultured with osteoblasts to evaluate the cytotoxicity of GTG composites by alive cell counting. In this study, the extracts were cocultured with the osteoblasts; thereafter, the concentration of transforming growth factor-, (TGF-,1) and prostaglandin E2 (PGE2) in the medium was analyzed to strictly reflect the biological effects of GTG composites on the growth of osteoblasts. In order to investigate the osteoconductive potential of the GTG composites on new bone formation in a relative short term, a model of neonatal rat calvarial organ culture was designed prior to animal experiments. Three experimental materials of 4, 8, and 12% GTG composites were evaluated by fetal rat calvarial organ culture for their ability for bone regeneration. Deproteinized bovine and porcine cancellous bone matrixes were used as the controlled materials. All the organ culture units were maintained in cultured medium for 5 weeks. Following the culture period, the morphology of tissue was observed under an optical microscope, and the quantitative evaluation of the new generation bone was determined by using a semiautomatic histomorphometeric method. Except in the initial 4 days, the concentration of TGF-,1 of 4% and 8% GTG composites was higher than that of the blank group for all the other experimental time periods. The PGE2 concentration for 4% and 8% GTG composites was lower than that of the blank group. It revealed that the 4% and 8% GTG composites would not lead to inflammation and would promote osteoblast growth. The morphology and activity of the osteoblasts were not transformed or changed by the 2 GTG composites. For the 12% GTG composite, the performance of the in vitro condition was inferior to the blank group and the other 2 GTG composites. Although the concentration of TGF-,1 and PGE2 was gradually back to normal after 14 days, the morphology of the osteoblasts was abnormal with features such as contracted cytoplast structures. The osteoblast was damaged perhaps in the initial stage. We suggested that the 4% and 8% GTG composites should be soaked in distilled water at least for 4 days before medical applications. The 12% GTG composite and the composites with a concentration of glutaraldehyde solution higher than 12% were not recommended as a medical prostheses in any condition. The fetal rat calvaria culture also showed the same results with the analysis of TGF-,1 and PGE2. From the study, we could predict the results of animal experiments in the future. [source]