The disciplines of astrobiology (AB) and space biology (SB) clearly have common interests, however they have not been pursued jointly.SB and AB, together with planetary protection and human spaceflight, are inextricably linked, both intellectually and technologically.They must now be linked operationally.

Inaugurated in 1998, the NASA Astrobiology Institute (NAI) is re-composed, repeatedly, by competitive peer-review selection of proposals submitted to Cooperative Agreement Notice opportunities. The NAI is a strategic investment of resources from the NASA Astrobiology Program to conduct demonstrably excellent interdisciplinary astrobiology research, train the next generations of astrobiologists, and act as a bridge between the astrobiology community and NASA’s planetary exploration and astronomical investigation missions. While pursuing these ends, we demonstrate the utility of information technology tools in increasing the effectiveness of a distributed, virtual institute and engage in outreach to the public, to our professional colleagues, and to the traditional education community. Currently, the NAI contains sixteen Teams. The spectrum of their research encompasses: 1) the birth of stars, 2) the formation of planetary systems from natal stellar molecular clouds, 3) the factors influencing the evolution of habitable worlds in the Solar System and in other planetary systems, 4) the emergence of life from universal physicochemical principles, 5) the evolution and diversity of life; from cellular building blocks to multi-cellular, differentiated, and specialized systems and the emergence of intelligence, 6) life’s strategies for thriving in environments that represent extreme limits, on Earth and with relation to extraterrestrial exploration and 7) the biosignatures characteristic of life. Clearly, the spectrum of NAI research overlaps substantially with the interests of ASGSB scientists with respect to the planetary context of biology and the environmental factors influencing living systems in, and their adaptation to, planetary, near-Earth and interplanetary space, and extraterrestrial environments.

AstrobiologyVol. 1, No. 3 Abstracts: NASA Astrobiology Institute General Meeting 2001Astrobiology: Bridging the Physical and Life SciencesEdward M. GoolishEdward M. GoolishSearch for more papers by this authorPublished Online:5 Jul 2004https://doi.org/10.1089/15311070152757500AboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail "Astrobiology: Bridging the Physical and Life Sciences." , 1(3), p. 292FiguresReferencesRelatedDetailsCited byAstrobiology LiteratureWatch5 July 2004 | Astrobiology, Vol. 1, No. 4 Volume 1Issue 3Sep 2001 To cite this article:Edward M. Goolish.Astrobiology: Bridging the Physical and Life Sciences.Astrobiology.Sep 2001.292-292.http://doi.org/10.1089/15311070152757500Published in Volume: 1 Issue 3: July 5, 2004PDF download

Previous reports of the behavior of aquatic organisms in the microgravity environment of space (~10(-6) g) or during the brief weightless period of parabolic flight indicate that most species display a dramatic "looping" or "circling" response (De Jong et al. 1996, Anken, Ibsch and Rahmann 1998). However, the behavior of aquatic species under hypergravity conditions is less clear. Our objectives in the present study were to examine the behavioral response of adult zebrafish (Danio rerio) to hypergravity conditions (2-g), quantify changes in adult swimbladder volume, and to determine if the larvae of zebrafish are capable of accessing the air-water interface for initial swimbladder inflation under hypergravity conditions.

Compared to a control gas bladder inflation rate of 95·1±1·9%, zebrafish Danio rerio larvae 72 h post‐fertilization maintained in closed chambers had an inflation rate of just 19·1±7·7%. Larval survivorship through 10 days in closed chambers (32%) was significantly less than that in open chambers (76%), and the extent of spinal curvature was significantly higher among larvae maintained in closed chambers. Larvae which failed to inflate their gas bladder showed very little change in body length, and had a final dry weight c. 14% of that for control larvae. The small number of larvae with inflated gas bladders found in closed chambers might be attributed to the inadvertent introduction of small bubbles into two replicates. These results indicate that access to an air‐water interface is critical for the normal development of zebrafish larvae, but also that a small, submerged, spherical gas volume may to a limited extent be used for initial gas bladder inflation.

Within the past decade the zebrafish or zebra danio Danio rerio has become a major vertebrate model for the study of developmental biology, neurobiology, and molecular genetics. Most research universities now include large zebrafish colonies where considerable resources are expended for their feeding and maintenance. Larvae are particularly labor intensive because they are commonly fed a live diet such as paramecia Paramecium sp. and brine shrimp Artemia sp. We evaluated 10 processed (i.e., nonliving) diets as alternatives to a live diet using the criteria of survivorship and growth during the 2-3 weeks following hatching. The test diets included commercial diets, two experimental diets, and freeze-dried brine shrimp. The control diet consisted of live paramecia and brine shrimp. Four experiments that varied in water exchange rate, aeration, and in the timing and method of diet delivery were conducted. No processed diet performed as well as the live-diet control when both larval survivorship and growth rate were considered. Furthermore, differences in water exchange rate and method of diet delivery were equally important in determining survivorship and growth as were differences among individual test diets. Under conditions when larval growth rate was similar to the live-diet control (hi,oh water exchange rate), survivorship was approximately 50% of the control value. Under conditions where larval survivorship was high (low water exchange rate), growth rate was 14-37% of the control value. Although no single test diet performed appreciably better than the others, the following general diet characteristics appeared to increase performance; resistance to breakdown, 200-400-mu m particle size, and a high residence time in the water column. Overall results suggest that processed diets for zebrafish larvae can be substituted for a live diet only if a decrease in either growth rate or survivorship is acceptable.

The zebrafish or zebra danio Danio (=Brachydanio) rerio has recently become a major vertebrate model for the study of developmental biology, neurobiology, and molecular genetics. As a result, most research universities have now invested considerable resources in the construction of large zebrafish facilities. A key element in the design of these facilities is maximizing the efficiency of available space. Here we report on the effects of aquarium chamber volume on the reproduction of zebrafish, with the objective of identifying the minimal volume required for normal egg production. Six adults (two males and four females) were tested in chamber volumes of 500, 400, 300, 200, and 100 mL. Results were compared with those from a control volume of 3.5 L. Eggs were removed from the test chambers after spawning and incubated in petri dishes at 28 degrees C. Total egg production, percent of eggs hatching, and larval length at 96 h postfertilization were used to evaluate breeding success. Compared with the control, egg production was not significantly affected by reduced aquaria volumes of 500, 400, and 300 mi,. However, mean egg production from a test volume of 200 mt was only 48% of the control egg production (P < 0.05), and at a test volume of 100 mt, egg production was reduced to 26% of the control value (P < 0.005). Percent egg hatch and 96-h larval length were not affected at any test volume.

Publisher Summary This chapter discusses the effect of body size on metabolism in fishes. There are no obvious direct effects of body size on cell metabolism because the size of individual cells remains relatively unchanged. With larger body size, cellular metabolism is increasingly removed from the environment by distance, and therefore also by time. The distancing between the cell and environment that occurs with increased body size will result in a decreased rate of delivery of these limiting factors. The chapter discusses the way discuss this limitation in the delivery of materials can be expected to influence the physiology and cellular metabolism of fish. It presents theoretical explanations for the negative allometry of aerobic metabolism and analyzes the scaling of maximum whole-body aerobic capacity. The chapter also describes symmorphosis and the scaling of individual respiratory traits and elaborates the effects of body size on anaerobic metabolism.

What bioenergetic characteristic of foraging is most important? Most ecologists will agree that the process which ultimately should be maximized is net energy gain over some meaningfully long period of time, and this is the criterion most widely employed by current optimal foraging theory (but see Pierce and Ollason 1987). The next question to ask is, what attribute of an animal's behavior should be studied to describe its foraging? Two general answers to this question have evolved, and they have resulted in what I will refer to, for purposes of discussion, as the selection and activity approaches to foraging. Behaviorists have almost without exception used the first of these, prey selection, as the attribute to quantify, analyze, and use to test optimal foraging models (Stephens and Krebs 1986). For a large group of others, however, foraging behavior is defined less by what an animal chooses to eat and more by actual patterns of locomotor and feeding activity. Strategies of foraging behavior have been identified by this second approach (such as the sit-and-wait through active continuum), which have been associated with particular physiological and morphological characteristics (Huey and Pianka 1981, Webb 1984, Feder and Lauder 1986). Because these two seemingly different approaches are studying the same phenomenon, foraging, it should be the case that there is a direct relationship between them. My aim here is to briefly comment on how these two views differ, how they may be related, and to suggest that for most carnivores an integrated approach is needed which combines both perspectives. The foraging models of the selection approach have focused on two basic problems: which prey item to consume and the related issue of when to leave a patch (Stephens and Krebs 1986). For many carnivores, however, focusing on prey choice results in an incomplete understanding of foraging behavior. Consider, for example, the foraging behaviors of a wolf and a large feline. Since both often choose deer-like prey from their environment, describing what each animal chooses does little to increase our understanding of how each is adapted to its environment. The primary difference which characterizes these two foraging behaviors is not what prey they feed upon, but rather the pattern of energy use to obtain it. Large feline behavior is typically characterized by long periods of waiting, when very little energy is expended, followed by a brief period of extremely high power output. In contrast, the wolf behavior consists of long periods in active search of prey often followed by a long chase to exhaustion. Similar comparisons come easily to mind. It is not, for example, the selection of prey which differentiates the foraging behavior of the small sit-and-wait mudminnow (Umbra limi) from the continuous filtering paddlefish (Polyodon spathula); both will feed on large zooplankton (Barbour 1951, Chilton et al. 1984). The significant difference between the behaviors of these fish (and the wolf and the feline) is the range and, in particular, the variance of the power used during foraging.

ABSTRACT Killifish, Fundulus heteroclitus, subjected to artificial lift above their center of gravity (10% of body weight) required a minimum of 7–8 days to resorb swimbladder gases completely. The swimbladders of some fish, however, did not fall below 50% of normal volume. The rate of increase in swimbladder volume upon removal of lift varied little among individuals, with approximately 6 days required for complete refilling. Previous deflation of the swimbladder (by syringe) did not result in faster or more complete gas resorption when the fish were subjected to artificial lift. This suggests that the constraint to resorption observed in some fish is not mechanical, e.g. connective tissue, but may reflect individual variability in perception of the stimulus. Swimbladder dry mass, which scaled as (body mass)0.79, was not affected by exposure to artificial lift. However, fish subjected to 7–11 days of artificial lift displayed slower rates of gas secretion upon removal of lift than control fish whose swimbladders had been evacuated by syringe. The initial rate was 65 % of that of control fish, with two additional days required to achieve normal buoyancy. Also, the rate of swimbladder gas resorption was 24 % faster the second time fish were exposed to artificial lift. These results demonstrate that the capacity for gas secretion and resorption can be altered by previous exposure to hydrostatic challenges. Killifish buoyancy, expressed as swimbladder volume per weight of the gas-free fish in water, fell from 0.95 to 0.70 ml g−1 after 5 days of exposure to water current. Removal of the pectoral fins eliminated 70% of this decrease, while removal of the pelvic fins had no effect. The rate of gas resorption by fish subjected to artificial lift was also not affected by removal of the pectoral fins. From these results it appears that the decrease in swimbladder volume in fish exposed to water currents is a consequence of lift forces produced by the pectoral fins, but that they are not required for regulation. Fish exposed to water currents or artificial lift swim with a head-down angle of attack. Theoretical estimates show that the vertical force component generated by this swimming behavior is of the appropriate magnitude to compensate for the additional lift. Fish confined in transparent cages near the surface of the water were less buoyant (0.91 ml g−1) than fish similarly maintained at the bottom of the tank (0.98 ml g−1). However, because this effect was small, 10% of swimbladder volume, visual perception of vertical position is apparently not the primary stimulus for volume regulation. Partial lift (2.65 % of body weight) resulted in the resorption of twice as much swimbladder gas when attachment was anterior to the fish’s center of gravity than when it was an equal distance posterior to the center of gravity. When equal amounts of partial lift and weight were added, lift anterior and weight posterior, no change in swimbladder volume occurred. With the position of these forces reversed, swimbladder volume increased by 31 % to 1.27 ml g−1. These results suggest that fish respond to pitching forces, i.e. longitudinal lift moments, as a stimulus for swimbladder gas secretion and resorption.

The potential for generating energy during swimming via anaerobic metabolism and the ability to recover from exhaustive activity were examined in an actively foraging (creek chub, Semotilus atromaculatus) and a characteristically sit-and-wait species of fish (mudminnow, Umbra limi). The anaerobic threshold, as measured by a rise in muscle lactate, occurred at a higher swimming speed for the creek chub (approximately 5 body lengths s-1) than for the mudminnow (approximately 2.0 body lengths s-1). Anaerobic scope, defined as the rate of muscle-lactate production during maximal spring activity, was 87% higher for the mudminnow (5.84-mu-mol g-1 min-1) than for the creek chub (3.13-mu-mol g-1 min-1). Whole-body anaerobic capacity at exhaustion (4 min) was also greater for mudminnows (9.82-mu-mol g-1) than for creek chubs (6.46-mu-mol g-1). The rate constant for muscle-lactate disappearance following exhaustion, however, was slightly higher for creek chubs (-0.63) than for mudminnows (-0.40). The time required for muscle-lactate concentration to return to resting values in these 1-2 g fish (4-6 h) was much less than previously reported times for large fish. Muscle-glucose concentration during recovery from 8 min of exhaustive activity was relatively unchanged in the creek chub but increased threefold in the mudminnow. The rate of increase in muscle-glycogen concentration following exhaustive activity was approximately sixfold higher for the mudminnow (23.6 mg [100 g]-1 h-1) than for the creek chub (3.7 mg [100 g]-1 h-1). Estimates of the time required for complete glycogen restoration were 6 h and 14 h for the mudminnow and creek chub, respectively. These results suggest that increased potential for and reliance on anaerobic energy production during swimming is characteristic of sit-and-wait foraging behavior in fish.

Biological ReviewsVolume 66, Issue 1 p. 33-56 AEROBIC AND ANAEROBIC SCALING IN FISH EDWARD M. GOOLISH, EDWARD M. GOOLISH University of Michigan, School of Natural Resources, Ann Arbor, MI 48109 U.S.ASearch for more papers by this author EDWARD M. GOOLISH, EDWARD M. GOOLISH University of Michigan, School of Natural Resources, Ann Arbor, MI 48109 U.S.ASearch for more papers by this author First published: February 1991 https://doi.org/10.1111/j.1469-185X.1991.tb01134.xCitations: 120AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume66, Issue1February 1991Pages 33-56 RelatedInformation

The intertidal copepod Tigriopus californicus (Baker) adjusts its intracellular free amino acid (FAA) content to regulate cell volume following osmotic stress. The near absence of either proline or alanine in the medium and increase in oxygen consumption suggests that these free amino acids are oxidized during hypoosmotic stress. The theoretical costs associated with the production of typical levels of proline and alanine following hyperosmotic stress (50 to 100% seawater) were estimated to be 116% of daily energy use. However, a decline in oxygen consumption rate following hyperosmotic stress was recorded, and thus supports the view that proline synthesis can interfere with Krebs cycle turnover. The rate of alanine accumulation under anoxic conditions was nearly the same as that following hyperosmotic stress but no accumulation of proline was observed. When hyperosmotically stressed under anoxic conditions, nearly 50% more alanine was accumulated by T. californicus than when only experiencing anoxia. In contrast, T. californicus under anoxic conditions accumulated only 13% of the proline normally produced following hyperosmotic stress. Copepods having high lipid levels showed a greater reliance on proline than alanine (5:1) following hyperosmotic stress compared with copepods with little or no lipid reserves (1:1). This shift in FAA accumulation from proline to alanine under restricted energy supply (i.e. anoxia and low-lipid level) would be energetically advantageous since alanine is much less costly to synthesize. The proportion of proline and alanine produced during hyperosmotic stress may be regulated at the pyruvate branch point. * Present address: Dr E. M. Goolish, School of Natural Resources, University of Michigan, Ann Arbor, Michigan 48109, USA. Key-words: Free amino acids, osmoregulation, Tigriopus californicus, anoxia, bioenergetics, oxygen consumption, salinity, alanine, proline

ABSTRACTThe scaling of anaerobic metabolism and red muscle mass was examined in rainbow trout (Salmo gairdneri) ranging in size from 2 to 1200 g. The initial rate of white muscle lactate production during maximal burst activity was significantly higher in large (28·lcm) than in small (8·0cm) fish. ‘Resting’ lactate concentrations in anesthetized trout (approximately 30 s of stress) increased with fish size, also reflecting higher glycolytic potential for larger fish. Maximum muscle lactate concentrations following 6 min of exhaustive exercise increased from approximately 25 to 45 μmolg−1 with increased fish size (= L0·36, where L is fish length). Total white muscle lactate production, including changes in muscle mass, scaled as L3·52. A scaling comparison of total anaerobic capacity with theoretically predicted power requirements indicated decreased burst swimming performance with increased size. Red muscle mass increased from approximately 1 to 3 % of body mass with increased fish size. The positive allometry in red muscle mass (= L3·62) is greater than the scaling of power requirements during aerobic swimming predicted from hydrodynamic theory, and may provide compensation for decreased mass-specific power output with increased size.

Journal of Fish BiologyVolume 35, Issue 4 p. 597-598 A comparison of oxygen debt in small and large rainbow trout, Salmo gairdneri Richardson E. M. Goolish, E. M. Goolish University of Michigan, School of Natural Resources, Ann Arbor, MI 48109, U.S.A. and Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Lowestoft, Suffolk, NR33 0HT, U.K.Search for more papers by this author E. M. Goolish, E. M. Goolish University of Michigan, School of Natural Resources, Ann Arbor, MI 48109, U.S.A. and Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Lowestoft, Suffolk, NR33 0HT, U.K.Search for more papers by this author First published: October 1989 https://doi.org/10.1111/j.1095-8649.1989.tb03010.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume35, Issue4October 1989Pages 597-598 RelatedInformation

Intracellular concentrations of free amino acids (FAA) in the intertidal copepodTigriopus californicus increase in response to hyperosmotic stress and decrease in response to hypo-osmotic stress. The purpose of this study was to determine if exposure to repeated bouts of osmotic stress resulted in changes in FAA accumulation or the degree of FAA retention in subsequent episodes. Five groups ofT. californicus were exposed for 22 days to a fluctuating salinity regime which consisted of 24 h at 100% seawater followed by 24 h at either 90, 80, 70, 60 or 50% seawater (11 cycles). After the tenth exposure to 100% seawater, individuals from each treatment group were analyzed for alanine and proline concentration. Alanine and proline accumulation generally increased in proportion to the osmotic stress up to 60–100% seawater — additional osmotic stress failed to increase total accumulation. Prior exposure to fluctuating salinity increased the extent of alanine and proline retention observed upon transfer to a hypo-osmotic medium. The treatment group which had experienced the most extreme fluctuation (50–100% seawater) retained alanine and proline levels approximately 10- and 20-fold higher, respectively, than controls. A less severe salinity fluctuation was required to elicit this response for alanine (90–100% seawater) than for proline (60–100% seawater). Previous exposure to fluctuating salinity also resulted in increased alanine and proline accumulation in subsequent episodes of hyperosmotic stress. 24 h after transfer from 50 to 100% seawater, alanine and proline levels in the conditioned copepods were approximately 3- and 7-fold higher, respectively, than in copepods which had not been cycled. This facilitation in alanine and proline accumulation occurred after 10 and 11 cycles, respectively. Of the increased accumulation in alanine and proline, 7.0% and 22.5%, respectively, could be accounted for by the higher degree of FAA retention while under hypo-osmotic conditions.

The aerobic enzyme cytochrome-c oxidase (CCO) was used as a measure of tissue-specific metabolic capacity. Changes in tissue CCO activity with increased body size were combined with allometric relationships for tissue weight to describe changes in energy use with increased body size. A large (common carp, Cyprinus carpio) and a small (common shiner, Notropis cornutus) species of cyprinid were used to examine differences between ontogenetic and phylogenetic allometry. With increased size, shifts occurred in energy use from viscera (high metabolic rate) to muscle tissue (low metabolic rate) which would account for the negative allometry of whole-body metabolic rate. This shift was more severe for the larger (i.e., faster growing) species, common carp. Percent muscle mass was fairly constant in the shiner, but increased from 42 to 62% of total body mass in the carp. For both species, the greatest allometry in total tissue CCO activity occurred in the brain and intestine. Total intestinal CCO activity scaled as weight to the exponents 0.70 and 0.54 for the carp and shiner, respectively. The greater proportion of metabolically active visceral tissue in young individuals is apparently not an energetic disadvantage, because these fish often have the highest growth efficiencies. These efficiencies may be due to the more favorable ratio of food "processing" capacity to target growth tissue (muscle) in small fish. The negative allometry in processing ability is likely responsible for the decreases in ingestion and growth rates with increased size. The influence of growth on ectotherm metabolism is large and, because growth is allometric, it can affect the exponent for metabolic rate in ontogenetic allometry studies.