1. Introduction
Ammonia is the major metabolic end product during the catabolism of proteins, amino acids and other nitrogen containing biomolecules in different animal tissues. Ammonia is very toxic to the fish. Its toxicity leads to reduced growth rate (Atwood et al., 2000; El-Shafai et al., 2004; Hegazi and Hasanein, 2010), disruption of ion-osmo homeostasis (Knoph and Thorud, 1996; Person-Le Ruyet et al., 2003, 1998), gill hyperplasia (Benli et al., 2008), and if present in very high concentration, it causes hyperexcitability, coma, convulsions and finally death (Ip et al., 2001b).
To survive the effect of the ammonia toxicity, fish modifies its metabolism by either decreasing the production of ammonia, increasing its excretion, or converting the ammonia to glutamine and/or urea (Ip et al., 2001b). Most of the freshwater teleosts are ammoniotelic, as they excrete ammonia as primary excretory product to the external environment mainly by diffusion through the gills (Saha and Ratha, 2007). But, several species of fish have adapted to unique environmental circumstances by expressing high levels of OUC-enzymes and thus converting more than 50% of waste nitrogen as urea-N, they are considered as ureotelic (Anderson, 2001; Saha and Ratha, 2007). Though, quite a few recent studies have proposed an alternate to ureotelism (i.e. increased OUC pathway activity) as a mechanism for responding to such environmental circumstances. For example, in marble goby (Oxyeleotris marmoratus) a facultative freshwater air-breather, which can tolerate continuous air exposure for up to a week, glutamine synthetase (GS) appears to function as ammonia trap (Jow et al., 1999). A similar observation was made in the swamp eel (Monopterus albus) (Tay et al.,...
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...) concentrations. Furthermore, water evaporation at the high temperatures of the tropics can concentrate external ammonia (EA) (Rao et al., 1994). The situation is further aggreavated for those fish living in rice fields, where agricultural fertilization can lead to high concentrations of EA (Rao et al., 1994).
In the present study presence of multiple GS mRNA transcripts and their differential expression pattern in tissues air-breathing walking catfish (C. batrachus) during exposure to high environmental ammonia (HEA) (50 mM NH4Cl) were investigated. In addition, attempts were made for characterization of different GS proteins, and for this integrated approaches of computational analysis and expression profiling were used to predict properties and features that may be important for their function and to elucidate its possible association with hyper-ammonia stress.
To begin the lab, the variable treatment was prepared as the Loggerlite probe, used to later measure oxygen consumption, warmed up for approximately 10 minutes. To prepare the variable treatment, 200ml of Sodium and Ammo-lock water was measured in a container and a pre-prepared “tea bag” of tobacco was steeped in the room temperature treated water until a light yellow color was visible. After preparing the tobacco solution the preparation for the live goldfish began as two beakers were filled with 100 ml of treated water. Each beaker was weighed before addi...
The procedures for this experiment are those that are referred to in Duncan and Townsend, 1996 p9-7. In our experiment however, each student group chose a temperature of either 5 C, 10 C, 15 C, or 20 C. Each group selected a crayfish, and placed it in an erlenmeyer flask filled with distilled water. The flask’s O2 levels had already been measured. the flask was then placed in a water bath of the selected temperature for thirty minutes, and then the O2 levels were measured again. Each group shared their findings with the class. The metabolic rates of the mouse were conducted by the instructor and distributed. We also did not use the Winkler method to measure the O2 levels. We used a measuring device instead.
The ineptitude of the monogastric animals to fully hydrolyze the phytic acid resulted in several problems. For instances, supplementation of inorganic phosphate, which is expensive, is needed to compensate with the inability of the monogastric animals to utilize phytic acid. The supplementation of inorganic phosphate in the animal feeds is crucial to meet the animals’ dietary requirements. Furthermore, the unutilized phytate-phosphorus causes the concentration of phosphorus in the animals’ excreta increases and this will indirectly contributes to serious phosphorus pollution complication (Pen et al., 1993; Volfova et al., 1994). Cyanobacterial blooms, hypoxia and death of marine animals have been reported to occur as a consequence of the eutrophication of the rivers by this excessive phosphorus (Mallin, 2000; Naqvi et al., 2000). In fact, phytic acid has been well-known for ...
10. Bustin SA (October 2000). "Absolute quantification of mRNA using real-time reverse transcription polymerase chain reaction assays". J.
In mammals, ammonia excretion is unsuitable for disposing of nitrogenous waste on land. Mammals would have to urinate profusely to eliminate ammonia because of the toxicity, which would have to transport through the animal to be excreted in an extremely dilute solution. However...
Ciguatoxin originates from dinoflagellate algae and most commonly from the coral reef species of algae called Gambierodiscus toxicus primarily in tropical and subtropical regions (Kipping, Eastcott, Sarangi, 2006). The algae are eaten by herbivorous fishes that absorb the toxin without any significant observable effect (Kipping, Eastcott, Sarangi, 2006). The toxins remain in all parts of the fish flesh but there are higher concentrations of toxin in the viscera, liver and gonads. Bioaccumulation occurs as ciguatoxin progresses up the food chain. The species of fish with the highest quantity of ciguatoxin are the larger predators, primarily sharks and barracouda (Dickey, Plakas, 2010). The process of digestion itself appears to potentiate the toxicity (Kipping, Eastcott, Sarangi, 2006). The toxin is odorless and tasteless. Contaminated fish have no distinct taste and are undetectable (Bavastrelli, Bertucci, Midulla, Giardini, & Sanguigni, n.d.). The ciguatera toxins are heat stable and thus are not destroyed by cooking, freezing or acid (Kipping, Eastcott, Sarangi, 2006). Pre-market testing for the presence of CTX is currently not possible due to a lack of existing rapid field testing methods (Report, 2013).
The Artemia franciscana can survive in extreme conditions of salinity, water depth, and temperature (Biology 108 laboratory manual, 2010), but do A. franciscana prefer these conditions or do they simply cope with their surroundings? This experiment explored the extent of the A. franciscanas preference towards three major stimuli: light, temperature, and acidity. A. franciscana are able to endure extreme temperature ranges from 6 ̊ C to 40 ̊ C, however since their optimal temperature for breeding is about room temperature it can be inferred that the A. franciscana will prefer this over other temperatures (Al Dhaheri and Drew, 2003). This is much the same in regards to acidity as Artemia franciscana, in general thrive in saline lakes, can survive pH ranges between 7 and 10 with 8 being ideal for cysts(eggs) to hatch (Al Dhaheri and Drew, 2003). Based on this fact alone the tested A. franciscana should show preference to higher pH levels. In nature A. franciscana feed by scraping food, such as algae, of rocks and can be classified as a bottom feeder; with this said, A. franciscana are usually located in shallow waters. In respect to the preference of light intensity, A. franciscana can be hypothesized to respond to light erratically (Fox, 2001; Al Dhaheri and Drew, 2003). Using these predictions, and the results of the experimentation on the A. franciscana and stimuli, we will be able to determine their preference towards light, temperature, and pH.
Le Quesne, Will,J.F., and John K. Pinnegar. "The Potential Impacts of Ocean Acidification: Scaling from Physiology to Fisheries*." Fish and Fisheries 13.3 (2012): 333-44. ProQuest. Web. 21 Apr. 2014.
Ammonia (NH3) concentration in biogas does not exceed 0.1 mg/m3. The presence of ammonia in higher concentration is attributed to the increased nitrogen content of the substrate used (e.g. poultry manure).
Osmoregulation is an example of an organism maintaining homeostasis. More specifically, osmoregulation involves an animal regulating osmotic pressure, or its fluid content. Brine shrimp, Artemia, use osmoregulation to regulate the saline levels of fluid within their body. Because brine shrimps live in seawater, an environment with a high saline concentration, they must actively excrete excess salt. Brine Shrimps use metepipodites as the location of the ion pump which secretes sodium. This is an active transport of ions because it is moving against the gradient, a higher salt content outside the body. The two following studies describe the environmental conditions ideal for brine shrimp and the possible genetic explanation for the osmoregulation of brine shrimp, respectively.
The other category of harmful algae kill without toxins. These are equipped with structures such as spines and serrated edges that allow them to lodge in fish gill tissues. When this occurs it causes irritation which leads to overproduction of mucus which eventually leads to death.
Oroian, Viman Oana I. "Damaging Effects of Overall Water Pollution." BioFlux (2010): 113-15. Web. 16 Apr. 2014.
Nitrogen is used by plants in order to synthesize protein peptide bonds and for cell growth. Not only is this nutrient required in the largest quantity by plants, but it is also the most frequently limiting factor when it comes to productivity in crops. Plants cannot use nitrogen in the air and in the soil system it is lost easily. Because of this plants are forced to obtain nitrogen in the form of nitrate and ammonium from the soil. Too much nitrate can cause a negative effect on the plant including nitrate toxicity. High levels of nitrate are not only bad for plants but can also be dangerous to animals or humans in their presence. Here I discuss the scientific evidence of the effects of nitrate accumulation on plants and the environment and argue that too much nitrate accumulation can be harmful to its surroundings.
First type of biogeochemical cycle is nitrogen cycle. Nitrogen is abundant and chemically inert gases, constitutes of about 78% of the atmosphere. According to Stevenson and Cole (1999), accumulation in soil happens through microbial fixation of nitrogen in the presence of ammonia, nitrate and nitrite; depletion exists in the process of crop removal, leaching and volatilization. In term of that, the process of releasing compound during decomposition is called mineralization. Mineralization process is carried out by the microorganisms in which it releases carbon, and also ammonium (Sprent, 1987). As a result, many kinds of organic reduce nitrogen present, like urea, organic bases, such as purines and pyrimidines, and amino compounds. Animals have nitrogenous wastes and will eventually produce lots of nitrogen (Sprent, 1987). Several pathways are illustrated throughout the nitrogen cycle, such as nitrogen fixation, ammonification, nitrification and denitrification. Gates (1921) stated that the process of converted gaseous nitrogen into ammonia or ammonium is nitrogen fixation, while ammonium can also be produced through the decaying of nitrogenous organic substance, which is called ammonification. Afte...