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2. Sizes, condition factors and sex ratios of the scattered populations of the small cichlid fish, Alcolapia grahami, that inhabits the lagoons and sites of Lake Magadi (Kenya), one of the most extreme aquatic habitat on Earth

Author

Maina, John N., Kavembe, Geraldine D., Papah, Michael B., Mashiteng, Reatlegile, Wood, Chris M., Bianchini, Adalto, Bianchini, Lucas F., Bergman, Harold L., Johannsson, Ora E., Laurent, Piere, Chevalier, Claudine, and Ojoo, Rodi O.

Published
2019
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3. Comments on ARCO's studies of riparian mammals on the upper Clark Fork River and Supplemental state report, Bergman, H.L. and M.J. Szumski, 1995 : continued studies on the exposure and injury from environmental metal contamination on semi-aquatic mammals in the upper Clark Fork River, Montana /

Author

Bergman, Harold L., McDonald, Lyman, Montana. Natural Resource Damage Program, Montana State Library (archive.org), Bergman, Harold L., McDonald, Lyman, and Montana. Natural Resource Damage Program

Subjects
Atlantic Richfield Co, Clark Fork Watershed (Mont. and Idaho), Ecology, Habitat, Mammals, Riparian animals
Published
1995

4. Biomarkers

Author

Huggett, Robert J., primary, Klmerle, Richard A., additional, Mehrle, Paul M., additional, and Bergman, Harold L., additional

Published
2018
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15. Mammalian metabolic rates in the hottest fish on earth

Author

Wood, Chris M., primary, Brix, Kevin V., additional, De Boeck, Gudrun, additional, Bergman, Harold L., additional, Bianchini, Adalto, additional, Bianchini, Lucas F., additional, Maina, John N., additional, Johannsson, Ora E., additional, Kavembe, Geraldine D., additional, Papah, Michael B., additional, Letura, Kisipan M., additional, and Ojoo, Rodi O., additional

Published
2016
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16. Metabolism and antioxidant defense in the larval chironomid Tanytarsus minutipalpus: Adjustments to diel variations in the extreme conditions of Lake Magadi

Author

Bianchini, Lucas F., primary, Wood, Chris M., additional, Bergman, Harold L., additional, Johannsson, Ora E., additional, Laurent, Pierre, additional, Chevalier, Claudine, additional, Kisipan, Mosiany L., additional, Kavembe, Geraldine D., additional, Papah, Michael B., additional, Brix, Kevin V., additional, De Boeck, Gudrun, additional, Maina, John N., additional, Ojoo, Rodi O., additional, and Bianchini, Adalto, additional

Published
2016
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19. Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species.

Author

Firkus, Tyler, Rahel, Frank J., Bergman, Harold L., and Cherrington, Brian D.

Subjects
FISHES, WATER temperature, EFFECT of human beings on fishes, FATHEAD minnow, VITELLOGENINS, THERMAL pollution
Abstract

We examined the spawning success of Fathead Minnows (Pimephales promelas) and Johnny Darters (Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures. [ABSTRACT FROM AUTHOR]

Published
2018
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21. Rh proteins and NH4+-activated Na+-ATPase in the Magadi tilapia (Alcolapia grahami), a 100% ureotelic teleost fish

Author

Wood, Chris M., primary, Nawata, C. Michele, additional, Wilson, Jonathan M., additional, Laurent, Pierre, additional, Chevalier, Claudine, additional, Bergman, Harold L., additional, Bianchini, Adalto, additional, Maina, John N., additional, Johannsson, Ora E., additional, Bianchini, Lucas F., additional, Kavembe, Geraldine D., additional, Papah, Michael B., additional, and Ojoo, Rodi O., additional

Published
2013
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23. Physiological and molecular characterization of urea transport by the gills of the Lake Magadi tilapia Alcolapia grahami

Author

Walsh, Patrick J., Grosell, Martin Hautopp, Goss, Greg G., Bergman, Harold L., Bergman, Annie N., Wilson, Paul, Laurent, Pierre, Alper, Seth L., Smith, Craig P., Kamunde, Collins N., Wood, Chris M., Walsh, Patrick J., Grosell, Martin Hautopp, Goss, Greg G., Bergman, Harold L., Bergman, Annie N., Wilson, Paul, Laurent, Pierre, Alper, Seth L., Smith, Craig P., Kamunde, Collins N., and Wood, Chris M.

Abstract

Alcolapia grahami, urea transporter gene, UT-A2, gills, nitrogen excretion, Lake Magadi tilapia

Published
2001

28. A New Approach to the Determination of Bioavailable Metals in Surface Waters

Author

WYOMING UNIV LARAMIE, Bergman, Harold L., MacRae, Russell K., WYOMING UNIV LARAMIE, Bergman, Harold L., and MacRae, Russell K.

Abstract

The goal of this research was to develop analytical methods capable of determining the concentration of toxic (bioavailable) forms of copper in natural surface waters. The approach should also be applicable to other metals. The approach was: (1) to determine the apparent binding affinity of the gills of fish and other aquatic biota for copper using novel competition bioassay and copper residue accumulation techniques; and (2) to modify the performance of commercial cation exchange resins or synthesize custom-made cation exchange resins, to match the copper binding affinity of fish and other aquatic biota. Using a range of procedures, the apparent copper binding affinities (log of the Apparent Binding Affinity (ABA)) were determined for rainbow trout gills (6.4-7. 2), brook trout gills (7.1-7.2), trout mucus (6.97.7), and Daphnia magna (6.6-8. 1). Based on these results an acceptable value for log ABA would be 7.6 for cation-exchange chromatography procedures to measure the bioavailable fraction of copper. Commercially available resins under a variety of conditions consistently had copper binding affinities that were 2 to 3 orders of magnitude higher than the measured values for aquatic biota. Custom cation exchange resins were synthesized and yielded binding affinities closer to that of aquatic biota, but additional work is needed to standardize and validate this approach. Bioavailability, Metals, Water quality, Copper, Aquatic biota, Toxicity, Fish.

Published
1994

37. A New Approach to the Determination of Bioavailable Metals in Surface Waters

Author

WYOMING UNIV LARAMIE, Bergman, Harold L., Swoboda-Colberg, Norbert, Smith, Darren E., MacRae, Russell K., WYOMING UNIV LARAMIE, Bergman, Harold L., Swoboda-Colberg, Norbert, Smith, Darren E., and MacRae, Russell K.

Abstract

The goal of this research project is to develop a biologically relevant method for fractionating aqueous metals into toxic (bioavailable) and non-toxic forms. The overall approach is: (1) to determine the binding affinity of the gills of fish and other aquatic animals for specific metals using a novel competition bioassay technique; (2) to operationally modify the performance characteristics of cation exchange chromatography to match the metal binding affinity for gill tissue; and (3) to validate and, as necessary, calibrate the cation exchange chromatography method so as to match the toxicity of the metal(s) to aquatic biota under differing water quality conditions. Progress to date includes compiling a library of copper-organic acid stability constants, and completing experiments designed to establish experimental conditions for copper-fish-organic acid competition bioassays. The ILL (incipient lethal level) of copper for rainbow trout was estimated, and the effect of calcium exposure and calcium acclimation concentration on copper toxicity was evaluated.

Published
1992

48. Rh proteins and NH4+ -activated Na+-ATPase in the Magadi tilapia (Alcolapia grahami), a 100% ureotelic teleost fish.

Author

Wood, Chris M., Nawata, C. Michele, Wilson, Jonathan M., Laurent, Pierre, Chevalier, Claudine, Bergman, Harold L., Bianchini, Adalto, Maina, John N., Johannsson, Ora E., Bianchini, Lucas F., Kavembe, Geraldine D., Papah, Michael B., and Ojoo, Rodi O.

Subjects
CICHLIDS, OSTEICHTHYES, GILLS, AMMONIA, HYDROCORTISONE, PROTEINS
Abstract

The small cichlid fish Alcolapia grahami lives in Lake Magadi, Kenya, one of the most extreme aquatic environments on Earth (pH ~10, carbonate alkalinity ~300mequivl-1). The Magadi tilapia is the only 100% ureotelic teleost; it normally excretes no ammonia. This is interpreted as an evolutionary adaptation to overcome the near impossibility of sustaining an NH3 diffusion gradient across the gills against the high external pH. In standard ammoniotelic teleosts, branchial ammonia excretion is facilitated by Rh glycoproteins, and cortisol plays a role in upregulating these carriers, together with other components of a transport metabolon, so as to actively excrete ammonia during high environmental ammonia (HEA) exposure. In Magadi tilapia, we show that at least three Rh proteins (Rhag, Rhbg and Rhcg2) are expressed at the mRNA level in various tissues, and are recognized in the gills by specific antibodies. During HEA exposure, plasma ammonia levels and urea excretion rates increase markedly, and mRNA expression for the branchial urea transporter mtUT is elevated. Plasma cortisol increases and branchial mRNAs for Rhbg, Rhcg2 and Na+,K+-ATPase are all upregulated. Enzymatic activity of the latter is activated preferentially by NH4 + (versus K+), suggesting it can function as an NH4 +-transporter. Model calculations suggest that active ammonia excretion against the gradient may become possible through a combination of Rh protein and NH4 +-activated Na+-ATPase function. [ABSTRACT FROM AUTHOR]

Published
2013
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