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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Variation in Nest Temperatures of the American Alligator Found on the Kennedy Space Center Merritt Island National Wildlife Refuge

Information on nest temperatures of the American Alligator (Alligator mississippiensis) constructed in the wild is limited. Nesting temperatures during a critical thermal sensitive period determine the sex of alligators and are therefore critical in establishing the sex biases in recruitment efforts of alligators within a given community. Nest components, varying environmental conditions, and global warming could have a significant impact on nest temperatures, thus affecting future generations of a given population. One hundred and seventy four programmable thermistors were inserted into fifty eight nests from 2010 through 2015 nesting cycles. Three thermistors were placed inside each nest cavity (one on top of the eggs, one in the middle of the eggs, and one at the bottom of the clutch of the eggs) to collect temperature profiles in the incubation chamber and throughout the entire incubation period. One thermistor was also placed near or above these nests to obtain an ambient air temperature profile. Once retrieved, data from these thermistors were downloaded to examine temperature profiles throughout the incubation period as well as during the period of sexual determination. These data would help establish survival rates related to nest temperature and predict sex ratio of recruited neonates at the Kennedy Space Center. Over three million temperatures have been recorded since 2010 for the alligator thermistor study giving us insight to the recruitment efforts found here. Precipitation was the largest influence on nesting temperatures outside of daily photoperiod, with immediate changes of up to eight degrees Celsius.

Alligator↗
NASA NTRS2016

Transcriptomic Response of Drosophila Melanogaster Pupae Developed in Hypergravity

The metamorphosis of Drosophila is evolutionarily adapted to Earth's gravity, and is a tightly regulated process. Deviation from 1g to microgravity or hypergravity can influence metamorphosis, and alter associated gene expression. Understanding the relationship between an altered gravity environment and developmental processes is important for NASA's space travel goals. In the present study, 20 female and 20 male synchronized (Canton S, 2 to 3day old) flies were allowed to lay eggs while being maintained in a hypergravity environment (3g). Centrifugation was briefly stopped to discard the parent flies after 24hrs of egg laying, and then immediately continued until the eggs developed into P6-staged pupae (25 - 43 hours after pupation initiation). Post hypergravity exposure, P6-staged pupae were collected, total RNA was extracted using Qiagen RNeasy mini kits. We used RNA-Seq and qRT-PCR techniques to profile global transcriptomic changes in early pupae exposed to chronic hypergravity. During the pupal stage, Drosophila relies upon gravitational cues for proper development. Assessing gene expression changes in the pupa under altered gravity conditions helps highlight gravity dependent genetic pathways. A robust transcriptional response was observed in hypergravity-exposed pupae compared to controls, with 1,513 genes showing a significant (q < 0.05) difference in gene expression. Five major biological processes were affected: ion transport, redox homeostasis, immune response, proteolysis, and cuticle development. This outlines the underlying molecular changes occurring in Drosophila pupae in response to hypergravity.

RNASeq↗
NASA NTRS1971

Embryogenesis in 100% O2 at reduced pressure.

Fertile chicken eggs were incubated in an altitude chamber in a near 100% O2 atmosphere at 225 torr. Both N2 and CO2 were kept under 0.5%. Temperature was a standard 37.5 C but a high relative humidity of 90% was required to prevent dehydration. In ten trials involving 382 eggs, hatchability averaged 21% of controls and weight of chicks was 11% less than controls, but embryo mortality was distributed similarly. Low pressure per se and small differences in O2 tension may have affected the results, but similarities to incubation in 21% O2-79% He call attention to absence of nitrogen as a possible explanation.

Weiss, H. S.↗
NASA NTRS1980

Evaluation of biological models using Spacelab

Biological models of hypogravity effects are described, including the cardiovascular-fluid shift, musculoskeletal, embryological and space sickness models. These models predict such effects as loss of extracellular fluid and electrolytes, decrease in red blood cell mass, and the loss of muscle and bone mass in weight-bearing portions of the body. Experimentation in Spacelab by the use of implanted electromagnetic flow probes, by fertilizing frog eggs in hypogravity and fixing the eggs at various stages of early development and by assessing the role of the vestibulocular reflex arc in space sickness is suggested. It is concluded that the use of small animals eliminates the uncertainties caused by corrective or preventive measures employed with human subjects.

Tollinger, D.↗
NASA NTRS1981

Experiment K-313: Rat and quail ontogenesis

The potential effects of spaceflight on the processes of mammalian fertilizaton, implantation and embryonic development are investigated. Five female and two male rats were placed together on Day 2 of the flight. By R+17, it was determined that both flight and synchronous females were not carrying normal pregnancies and three of the flight animals were laparotomized. The uterus and ovaries were processed for microscopic analyses. The two remaining flight females were allowed to recover from the exploratory operation, rebred with flight males and delivered normal litters. As a control for potential transplacental effects that might be interpreted as direct spaceflight effects, a series of fertilized Japanese quail (Coturnix japonica) eggs was flown on Cosmos 1129. Although all of the eggs were adversely impacted by an inflight failure of the incubator humidifier on flight Day 13, several embryos were able to progress to a developmental stage equivalent to that of a control 10-12 Day embryo.

Keefe, J. R.↗
NASA NTRS1982

Embryonic development during chronic acceleration

Experiments carried out on chicken eggs indicate that the embryo is affected during very early development, especially over the first four days, and during hatching. In the first four days, the brain develops as well as the anlage for all other organs. In addition, the heart commences to function and the extraembryonic membranes that compartmentalize the egg contents form. The latter require an appreciable extension and folding of tissue which may be disrupted by the mechanical load. Observations of embryonic abnormalities that occur during chronic acceleration suggest an inhibition of development of the axial skeleton, which is rarely seen otherwise, a general retardation of embryonic growth, and circulatory problems. The final stages of development (after 18 days) involve the uptake of fluids, the transition to aerial respiration, and the reorientation of the embryo into a normal hatching position. At 4 G mortality is very high during this period, with a majority of embryos failing to reorient into the normal hatching position.

Smith, A. H.↗
NASA NTRS1983

The first dedicated life sciences mission - Spacelab 4

The details of the payload and the experiments in Spacelab 4, the first Spacelab mission dedicated entirely to the life sciences, are discussed. The payload of Spacelab 4, carried in the bay of the Shuttle Orbiter, consists of 25 tentatively selected investigations combined into a comprehensive integrated exploration of the effects of acute weightlessness on living systems. The payload contains complementary designs in the human and animal investigations in order to validate animal models of human physiology in weightlessness. Animals used as experimental subjects will include squirrel monkeys, laboratory rats, several species of plants, and frog eggs. The main scientific objectives of the investigations include the study of the acute cephalic fluid shift, cardiovascular adaptation to weightlessness, including postflight reductions in orthostatic tolerance and exercise capacity, and changes in vestibular function, including space motion sickness, associated with weightlessness. Other scientific objective include the study of red cell mass reduction, negative nitrogen balance, altered calcium metabolism, suppressed in vitro lymphocyte reactivity, gravitropism and photropism in plants, and fertilization and early development in frog eggs.

Cramer, D. R.↗
NASA NTRS1983

Local Calcium Entry and the Guidance of Growth

The role of calcium in developing cells is illustrated. The Fucus egg, a brown algae is used to describe this phenomenom. Results of local calcium entry and forced calcium entry into the eggs are given.

Robinson, K. R.↗
NASA NTRS1983

Avian embryonic development in hyperdynamic environments

Embryos which developed for 24 hours in the oviduct of hens maintained at 2 G and which were subsequently incubated at Earth gravity had a 14% reduction in hatchability. Increased mortality during the first 4 days, and an increase in embryonic abnormalities were of the types usually found during the first mortality peak (2-3 days). Embryos in eggs that were produced at Earth gravity and continued their development on the centrifuge at fields of 2 G or less did not appear to be greatly affected by the treatment. At 4 G, 91% of the embryos died, mostly on the first and second days of incubation. Abnormalities prominent in the centrifuged eggs include: (a) a failure of the primitive streak to develop; (b) interference with the development of the axial skeleton; (c) multiple hemorrhages, mostly petechial which is consistent with capillary fragility; and (d) retardation of embryo growth, possibly caused by an interference with gaseous diffusion, the result of an acceleration-induced increase in gas density in the centrifuging incubator.

Abbott, U. K.↗
NASA NTRS1984

Gypsy moths and American dog ticks: Space partners

An experiment intended for the space shuttle and designed to investigate the effects of weightlessness and total darkness on gypsy moth eggs and engorged American dog ticks is described. The objectives are: (1) to reevaluate the effects of zero gravity on the termination of diapause/hibernation of embryonated gypsy moth eggs, (2) to determine the effect of zero gravity on the ovipositions and subsequent hatch from engorged female American dog ticks that have been induced to diapause in the laboratory, and (3) to determine whether morphological or biochemical changes occur in the insects under examination. Results will be compared with those from a similar experiment conducted on Skylab 4.

Hayes, D. K.↗
NASA NTRS1985

Report of the Avian Development Working Group

The anteroposterior axis of the avian embryo is established before it is laid. Baer's rule states that the cephalic end of the avian embryo will be away from the observer when the pointed end of the shell is on the observer's right. There are experimental data available which indicate gravity has a role in the establishment of the anteroposterior axis while the egg is in the uterus; this results in Baer's rule. The influence of gravity on egg development is studied.

Fallon, J. F.↗
NASA NTRS1985

Report of the Insect Development Group

Drosophila metanogaster was chosen as the insect species of choice, in regard to gravity response experiments involving normal reproduction and develop different strains. The specific gravity responses which might be affected by microgravity and are exhibited in normal reproduction and development include normal flight for courtship, mating and oviposition, tropisms for pupating or emergency of the adult, and crawling for gettering food by the larval instars at the organismic level. At the suborganismic elevel, it is believed that maturation of developing eggs in the virgin female and embryonic development of the developing egg could be affected by microgravity and warrant study.

Rockstein, M.↗
NASA NTRS1987

Amphibian development in microgravity

The results of experiments performed by the U.S. Biosatellites 1 and 2 and the Gemini VIII and XII missions and by the Soviet Salyut and Soyuz missions on the effect of gravity on the development of prefertilized amphibian egg and, in particular, of the vestibular system of amphibian embryo are described. In these experiments, the condition of microgravity was reached only after the prefertilized eggs were in the early stages of first cell division or in the blastula stage. No significant changes were observed in the morphology of the embryos or in the vestibular system of embyos developed, respectively, for 2-5 days or 20 days under conditions of microgravity. Experiments planned for future spaceflights are discussed.

Souza, K. A.↗
NASA NTRS1988

Diachronism between extinction time of terrestrial and marine dinosaurs

The dinosaur eggs of southern France occur in continental, fine-grained red-beds, rich in carbonate. The last eggs in the region occur in the magnetic polarity interval 30 normal. Estimates of the accumulation rate of these sediments on the basis of the magneto-stratigraphy leads to placement of the time of disappearance of the dinosaurs in this region of 200,000 to 400,000 years earlier than the Cretaceous-Tertiary boundary. In the Red Deer Valley, Canada, estimates of average accumulation rate lead to a time of disappearance of the dinosaurs of 135,000 to 157,000 years earlier than the Cretaceous-Tertiary boundary. In the central part of Poland, in the Nasilow Quarry, the paleomagnetic pattern shows 7 m of chalk of reversed polarity containing in its upper part the marine Cretaceous-Tertiary biostratigraphic boundary. A greensand deposit contains numerous re-deposited Maastrichtian fossils. The fossils show no signs of wear and are of very different sizes including 1 mm thick juvenile belemnites. The deposit was described as a lag-sediment. Among the various fossils are teeth of mosasaurs. Thus there is coincidence in time between the extinction of mosasaurs and other Cretaceous organisms. This leads to the conclusion, that extinction of terrestrial dinosaurs took place earlier than extinction of marine dinosaurs at the Cretaceous-Tertiary boundary.

Hansen, H. J.↗
NASA NTRS1990

Mars penetrator sample retrieval system

Three University of Wisconsin-Madison space studies are discussed briefly. The Mars Penetrator Retrieval System, used to acquire and analyze soil samples from a region approximately 15 to 30 feet below the Martian surface, uses a drill bit with three cutting tips arranged in a radially terraced formation. A prototype was built and tested. The Mars Egg is a small surface analyzer that would be dropped on the surface of Mars from an orbiter and would analyze the gases present in the surface soil over a period of one Martian year to determine the diffusivity of the soil. The egg contains a gas chromatograph, radio transmitter, and the necessary power supplies. Also discussed is the design of a GeoShack, a manned or unmanned mini-space station in geosynchronous orbit, designed for the repair, attitude correction, and general upkeep of satellites in geosynchnonous orbit.

Source record↗
NASA NTRS1990

Crystallization of proteins by dynamic control of supersaturation

The growth of protein crystals is known to be the limiting factor in the determination of the three-dimensional structures of most proteins. It is expected that the kinetics of supersaturation, which is directly related to solvent evaporation, will affect protein crystal growth and nucleation and accordingly determine the quality, number, size, and morphology of the crystals. With a technique that controls the evaporation of solvent from a protein solution with N2(g) it is possible to determine the effect of different evaporation profiles on hen egg white lysozyme crystals. Hen egg white lysozyme was chosen as the model protein because it crystallizes easily and has solubility data available for most salt, pH, and temperature ranges. Commercially available lysozyme was further purified by a number of methods. Crystals grown with the purified lysozyme and with the unpurified lysozyme in citrate buffer were different shapes but were found to be of the same symmetry space group by precession photos. Differences were seen in the lysozyme crystals grown using different evaporation rates. At three of the four initial conditions for lysozyme crystal growth, longer evaporation times yielded better crystals. The evaporation times required to see a change in the appearance of the crystals was much longer than expected. The number of rates studied so far represent only a small fraction of the ones now available with the gas evaporation device. The technique also provides for control of both solution pH and temperature which are related to the solubilities of proteins.

Wilson, Lori June↗
NASA NTRS1992

The effect of space environment on the development and aging of Drosophila Melanogaster (7-IML-1)

This experiment involves the study of the development of eggs of the fly, Drosophila, exposed to microgravity. It is presumed that oogenesis, rather than further states of embryonic development, is sensitive to gravity. This hypothesis will be tested by collecting eggs layered at specific times inflight and postflight from flies exposed to 0 and 1 g. This portion of the experiment is a repetition of an earlier experiment flown in Biorack during the Spacelab D1 Mission. An added feature of the experiment for the First International Microgravity Laboratory (IML-1) Mission is to study the effect of microgravity on the life span of Drosophila male flies. Various aspects of the investigation are discussed.

Marco, Roberto↗
NASA NTRS1992

Embryogenesis and organogenesis of Carausius morosus under space flight conditions (7-IML-1)

The experiment is part of a radiobiological space research program to obtain experimental data on the biological effectiveness of the structured component of cosmic radiation during spaceflight. In this proposed experiment, Carausius morosus embryos of different ages will develop under spaceflight conditions. The experiment is designed to determine the influence of galactic heavy ions of very high energy deposition in microgravity on developmental processes of different radiation sensitivity and regenerative capacity. Layers of Carausius morosus eggs are sandwiched between different track detectors (cellulose nitrate, CR39). This method allows the localization of the trajectory of each heavy ion in the biological layer and the identification of the site of the penetration inside the egg.

Buecker, D. H.↗