SP-401 Skylab, Classroom in Space

[50] Part II - Student Experiments

 

Chapter 4: Cells in Space.

picture of a Saturn IB launch
 

[51] Just as the atom is fundamental to all matter, the cell-composed of atoms-is fundamental to all living organisms. A cell can be an extremely complex thing, as found in higher forms of life, or a relatively simple one such as those characteristic of micro-organisms.

The knowledge and study of micro-organisms and the cellular basis of life was impossible until the invention of the microscope. The observance of such organisms was first reported more than 300 years ago by Anton van Leeuwenhoek, a Dutch scientist. At about the same time, an English physicist, Robert Hooke, conceived of the cell concept during his examination of a sample of cork with the microscope. The term "cell" was used because of the similarity of what he saw to the cells of a beehive. The improvements in microscopes through the ensuing years greatly increased our knowledge of micro-organisms. However, only with the advent of the electron microscope, which can magnify up to l million times, were we able to solve the mysteries of the cell.

Several Skylab student experiments were proposed to investigate various aspects of cellular behavior. These included the study of bacterial growth, immunology, the streaming of cytoplasm in a plant, and micro-organisms.

 

Bacteria and Spores

An experiment involving bacteria and spores was proposed by Robert L. Staehle of Harley School, Rochester, N.Y. He wanted to determine the effects of the Skylab environment (particularly weightlessness) on the survival, growth rates, and mutations of certain bacteria and spores.

Live bacteria (Bacillus subtillus and Escherichia coli), grown from a broth culture by Staehle at the laboratories of Rochester Institute of Technology, were suspended in a water solution of polyvinyl alcohol (PVA). The PVA was used to keep the bacteria alive but dormant until the experiment could be started. The solution was then dispensed on the surface of a disk of filter paper, where the bacteria remained in a vegetative form or reverted to a spore stage. The PVA coating on the bacteria protected them during the required storage period and enabled the establishment of an excellent growth condition when the filter paper was placed on the surface of nutrient agar.

Fifteen petri dishes containing nutrient agar, together with one petri dish containing 15 filter disks of bacteria, were launched in Skylab. Each inoculated disk was sandwiched between sterile paper disks for additional protection and isolation.

The experiment was initiated by placing a single bacteria and spore impregnated disk in each of the agar-filled petri dishes. Very shortly after that inoculation procedure, the water from the agar dissolved the PVA and provided nutrients to the bacteria and spores. Nine of the petri dishes were placed in an incubator at approximately 95°F, and six were incubated at the Skylab ambient temperature of approximately 77°F.

 


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two pictures of  Robert L. Staehle

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Robert L. Staehle, shown above with his science adviser Steven Hall, believed that Skylab would be a unique laboratory in which to study the effects of weightlessness on the survival, growth, and mutations in bacteria and spores. He later became a <<co-op>> student at Purdue University, alternately studying aeronautical engineering and working at the Marshall Space Flight Center.

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Robert L. Staehle, shown above with his science adviser Steven Hall, believed that Skylab would be a unique laboratory in which to study the effects of weightlessness on the survival, growth, and mutations in bacteria and spores. He later became a "co-op" student at Purdue University, alternately studying aeronautical engineering and working at the Marshall Space Flight Center.


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The heart of Staehle's experimental apparatus was a filterpaper disk impregnated with a bacterial culture suspended in polyvinyl alcohol and placed within an agar-filled petri dish.

The heart of Staehle's experimental apparatus was a filterpaper disk impregnated with a bacterial culture suspended in polyvinyl alcohol and placed within an agar-filled petri dish.

 


The experiment developed by Staehle fitted neatly into a standard Skylab food container, shown above. Its 16 petri dishes and associated equipment are shown below the food container.

The experiment developed by Staehle fitted neatly into a standard Skylab food container, shown above. Its 16 petri dishes and associated equipment are shown below the food container.

 

The petri dishes were incubated for 68 hours. Photographs were made of the bacterial colonies periodically throughout the incubation period to record the colony growth rates. Return of the petri dishes by the astronauts at the end of the first mission revealed that only a small portion of B. subtillus and none of the E. coli had developed. This result was not surprising in view of the overheating of Skylab after the loss of its meteoroid shield during launch.

As a result, a repetition of the experiment during the third mission was authorized, and the species Bacillus mycoides was selected to replace the E. coli. The same protocol or experimental procedure was repeated, except that the petri dishes were incubated for 88 hours. Once again, however, only B. subtillus colonies developed.

 


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To prepare the Staehle's experiment, individual petri dishes (1) were inoculated by the astronaut (2). The dishes were then incubated in a special owen (3) and within ambient Skylab temperatures (4).

To prepare the Staehle's experiment, individual petri dishes (1) were inoculated by the astronaut (2). The dishes were then incubated in a special owen (3) and within ambient Skylab temperatures (4).


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Pictures 1 and 2 show samples of Bacillus subtillus grown during the first performance of Staehle's experiment aboard Skylab. Pictures 3 and 4 show colonies of the same bacteria that developed during the second performance of the experiment.

Pictures 1 and 2 show samples of Bacillus subtillus grown during the first performance of Staehle's experiment aboard Skylab. Pictures 3 and 4 show colonies of the same bacteria that developed during the second performance of the experiment.


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The growth rate of Bacillus subtillus during the second performance of Staehle's experiment is shown here. The times shown represent the period from initiation of the experiment until the picture was taken.

The growth rate of Bacillus subtillus during the second performance of Staehle's experiment is shown here. The times shown represent the period from initiation of the experiment until the picture was taken.


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Scientist Pilot Kerwin performed Staehle's experiment during the first Skylab mission, using a small microscope to examine bacteria and spore changes.

Scientist Pilot Kerwin performed Staehle's experiment during the first Skylab mission, using a small microscope to examine bacteria and spore changes.

 

In general, fewer bacterial colonies developed aboard Skylab than in control experiments on Earth. But those that did develop on Skylab were usually larger, grew faster, and were more irregular or asymmetrical that the control colonies. There was wide variation in texture, shape, size, and topography (surface irregularity) among the colonies returned from the first visit. For some unexplained reason, many of the colonies' edges grew curled away from the surface of the disk.

The B. subtillus colonies from the third mission grew up to 50 percent larger than identically prepared and incubated control colonies on Earth.

The individual cells grew larger in diameter but did not significantly increase in number. The Skylab colonies exhibited a more pronounced topography. They also appeared to be somewhat more sensitive to several antibiotics to which they were exposed upon return to Earth.

The implications of Staehle's experiment have not yet been fully resolved. The descendants of the bacteria that spent their entire life cycle in the zero gravity of Skylab were scheduled to be observed for many generations. The effort to understand the effects of long-term spaceflight on bacteria has just begun.

 


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Colonies of Bacillus subtillus cultured on Skylab are shown in dish No. 1, while a colony grown under the same ambient conditions on Earth, with the exception of weightlessness, is shown in dish No. 2. For comparison, dish No. 3 shows bacteria cultivated under standard laboratory conditions on Earth.

Colonies of Bacillus subtillus cultured on Skylab are shown in dish No. 1, while a colony grown under the same ambient conditions on Earth, with the exception of weightlessness, is shown in dish No. 2. For comparison, dish No. 3 shows bacteria cultivated under standard laboratory conditions on Earth.

 

In-vitro Immunology

The hum an body constantly resists infection from invasion by harmful micro-organisms. This resistance, called an immune reaction, also guards against the introduction of foreign tissue. The study of this process is called immunology. If the study is conducted with living organisms, it is called in vivo, if conducted in a test tube, it is called in vitro.

An invading organism usually contains a specific protein or carbohydrate that stimulates immune reaction. The invading organism is called an antigen and reacts with the host's blood cells, which produce antibodies to counteract it. These antibodies attack and neutralize invading organisms in various ways. Some, called precipitins, precipitate the antigens so that they can be discharged from the host. Some produce agglutinins which cause clumping of bacteria and thus prevent their spread.

The study of this antigen-antibody reaction in space was proposed as a Skylab experiment by Todd A. Meister of the Bronx High School of Science, Jackson Heights, N.Y. He suggested an in vitro observation of the effects of zero gravity on a precipitin-type antigen-antibody reaction, as compared with the same reaction carried out in an Earth-based laboratory.

The experiment consisted of three plates containing agar and antibodies, three prefilled syringes containing dilutions of human antigen test inoculations (inoculum), and a cooler in which the....

 


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picture of Todd A. Meister

Todd A. Meister, shown with science adviser Robert Allen, proposed using Skylab to study the reaction of antigens and antibodies in a weightless environment. After graduating from high school, he entered medical college to major in neurosurgery.

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Todd A. Meister, shown with science adviser Robert Allen, proposed using Skylab to study the reaction of antigens and antibodies in a weightless environment. After graduating from high school, he entered medical college to major in neurosurgery.

 

.....containers of antigens and antibodies were stored. The cooler was installed in a locker in the Apollo spacecraft 15 hours prior to launch of the second crew. After docking with Skylab, it was transferred to the work area in the wardroom. To initiate the experiment, a measured amount of antigen was placed in the agar holes. Each plate was provided with a different combination of antigen/antibody. The plates were then stored at Skylab's room temperature for approximately 2 days. Photographs of the three chambers were taken about every 5 hours, starting 24 hours after the inoculation and continuing through the 2-day incubation period, so that the growth rate of the precipitin rings could be compared with those in the control experiment on Earth.

The crew reported that 5 to 10 minutes after inoculation, the agar had absorbed all of the antigen, as expected. The astronauts later observed that the small rings which grew during the 48-hour duration of the experiment were visible in only....

 


Meister's experiment was packaged in an ordinary thermos bottle that had been modified slightly to hold the syringes containing antigens and immunodiffusion plates with antibodies.

Meister's experiment was packaged in an ordinary thermos bottle that had been modified slightly to hold the syringes containing antigens and immunodiffusion plates with antibodies. The white device on the left was part of the packing, while the aluminum cans on the right held ice for cooling the experiment.


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To perform Meister's experiment, Scientist Pilot Garriot (1) first removed the protective packing from the thermos bottle, (2), took out the immunodiffusion plates, (3), attached them to the workbench, (4), and then filled the wells of the plates with antigens from the syringes.

To perform Meister's experiment, Scientist Pilot Garriot (1) first removed the protective packing from the thermos bottle, (2), took out the immunodiffusion plates, (3), attached them to the workbench, (4), and then filled the wells of the plates with antigens from the syringes.


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Meister periodically examined control plates in the research laboratory of Rensselaer Polytechnic Institute as his experiment progressed aboard Skylab.

Meister periodically examined control plates in the research laboratory of Rensselaer Polytechnic Institute as his experiment progressed aboard Skylab.


Precipitin rings are seen as cloudy circles surrounding the well into which antigens were introduced. They were formed by the reaction of the antigen to the antibodies in the agar of the plate.

Precipitin rings are seen as cloudy circles surrounding the well into which antigens were introduced. They were formed by the reaction of the antigen to the antibodies in the agar of the plate.

 

...some of the chambers. Thirty-nine still photographs of the chambers were taken.

In analyzing the photographs after the mission, Meister observed that much of the agar within the plates had dried and cracked. Evidence of this drying appeared in photographs taken after 23 hours of incubation. The drying of the agar probably contributed to the failure of some of the chambers to exhibit precipitin rings. Additionally, the agar could have separated from the chamber, allowing antigen to spread under it. These complications prevented the precipitin rings from forming in 9 of the 18 chambers.

The nine precipitin rings that did appear formed at approximately the same growth rates and with similar intensities as those in control experiments on Earth. The conclusion is that this segment of....

 


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picture of Cheryl A. Peltz

Cheryl A. Peltz proposed an experiment to investigate the phenomenon of cytoplasmic streaming or circulation of materials within the cells of a water plant named Elodea (commonly called water weed or water thyme).

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Cheryl A. Peltz proposed an experiment to investigate the phenomenon of cytoplasmic streaming or circulation of materials within the cells of a water plant named Elodea (commonly called water weed or water thyme).

 

.....the immune reaction system functioned normally in the Skylab environment.

 

Cytoplasmic Streaming

An experiment to observe the effects of zero gravity on cytoplasmic streaming in the aquatic plant elodea was proposed by Cheryl A. Peltz of Arapahoe High School, Littleton, Colo.

The phenomenon of cytoplasmic streaming is not well understood, but it is recognized as the circulation mechanism of the internal materials, or cytoplasm, of a cell. Cytoplasm is a gelatinous substance that has the ability to change its viscosity and flow, carrying various cell materials with it. The activity can be stimulated by sunlight or heat. Through this flow, the cytoplasm appears to place the cell's chloroplasts, or chlorophyll receptacles, in the optimum position for photosynthesis. The conversion of carbon dioxide and water into oxygen and sugar, and the oxidation of sugar and its conversion to starch, is a process requiring an interchange of these compounds among the various parts of a cell. Cytoplasmic streaming is believed to be a transport mechanism for the exchange of...

 


Elodea was selected because its leaf simplifies preparation of specimens for microscopic examination.

Elodea was selected because its leaf simplifies preparation of specimens for microscopic examination.


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At a magnification of 450X, the structural components of the Elodea cells can be clearly seen.

At a magnification of 450X, the structural components of the Elodea cells can be clearly seen. The small spheroid elements within each cell are chloroplasts. In the presence of light, they convert carbon dioxide and water into oxygen and sugar.

 

.....proteins and byproducts among the cell components.

The experiment utilized three vials containing elodea sprigs suspended in a nutrient agar solution, a set of microscope slides and cover slips, and a pair of tweezers, all packaged in a container. Support equipment included a microscope, a microscope-camera adapter, and a 1 6-millimeter motion picture camera. Three additional vials containing elodea were prepared as control units on Earth.

The Skylab vials were loaded aboard the Apollo spacecraft prior to launch of the second crew, and the control units were stored in a similar environment on the ground. The experiment timetable called for a maximum of 6 days of storage during the launch, docking, and preparation portions of flight. Once aboard Skylab, the vials were to be placed in an open area near a source of light. Experiment scheduling difficulties delayed the deployment until the 8th day. When the experiment was finally performed on the 15th day, the crew reported that the plants had died, probably because of the 2 unscheduled days of darkness. The control plants were stored and deployed on the same schedule and, hence, were also dead.

The experiment was rescheduled for the 3d mission, and the plant vials were packaged in transparent containers to allow exposure to ambient light. The first observation was made on the 11 th day of the mission, and streaming was observed. In a second observation of the plants on the 18th day, no streaming could be detected. The returned film verified that the plants had died by that time. Unfortunately, the film of streaming from the first observation was improperly exposed, and comparison to cytoplasmic streaming on Earth was limited to the crew's observation that it appeared the same as it had during training.

The control elodea plants survived longer than [64] those on Skylab. Ms. Peltz inferred that in addition to the problem of excessive dark periods, it may have been difficult for the plants' waste products to diffuse away from the leaf surface in conditions of zero gravity. In other words, the elodea on Skylab may have "smothered" in oxygen, unable to obtain necessary carbon dioxide for photosynthesis.

She further believed that future research of fundamental plant-cell processes in space must be pursued. The ability of the human being to exist for as long as 3 months in space was proved by the men of Skylab, but an understanding of any adaptations required for truly long-term exposure to zero gravity must begin with research at the cellular level.

 

Micro-Organisms in Varying Gravity

Keith Stein of W. Tresper Clarke High School, Westbury, N.Y., proposed a highly sophisticated experiment to assess the effects of both zero gravity and various levels of gravitational forces on several species of micro-organisms and enzyme action.

As an elementary life form, micro-organisms can provide the first step in the chain of investigations leading ultimately to the effects of adverse environments on higher life forms, including man. The concept of the experiment required a microorganism that utilized carbon dioxide to generate oxygen as well as to provide a potential food source for man. Stein wanted to investigate the impacts of the orbital environment, the launch and reentry accelerations, and the effects of prolonged weightlessness. He proposed a large number of samples and a rigidly controlled regime for his experiment.

Stein's concept proposed two centrifuges rotating in opposite directions to minimize the interchange of angular momentum with the Skylab. Sample containers were to be placed at different radii on the centrifuge to produce simulated gravitational forces ranging from 1g to near 0g.

Clearly, the development time for such a centrifuge, the special purpose microscope, and the camera, together with the large amount of crew time and film required to obtain data, made it impractical.

As a result, Stein became affiliated with microbiologists at the Johnson Space Center. J. K. ....

 


Garriott performed the cytoplasmic streaming experiment by first attaching a camera to the Skylab microscope (1). He then opened the vial containing the plant (2), and examined the specimen visually (3) before placing it under the microscope for filming.

Garriott performed the cytoplasmic streaming experiment by first attaching a camera to the Skylab microscope (1). He then opened the vial containing the plant (2), and examined the specimen visually (3) before placing it under the microscope for filming.


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Keith Stein proposed a very sophisticated and ambitious experiment to use Skylab for studying the effects of varying degrees of gravity, produced by a centrifuge, on several species of micro-organisms and enzymes. While it proved beyond the resources and time available in the program, he was affiliated with scientists who studied the microbial environment of the space station. He is shown above with science adviser Robert Allen.

picture of Keith Stein

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Keith Stein proposed a very sophisticated and ambitious experiment to use Skylab for studying the effects of varying degrees of gravity, produced by a centrifuge, on several species of micro-organisms and enzymes. While it proved beyond the resources and time available in the program, he was affiliated with scientists who studied the microbial environment of the space station. He is shown above with science adviser Robert Allen.

 

....Ferguson was investigating the microbial environment on Skylab. Through Dr. Ferguson's efforts, Stein was provided with bacteriological samples from Skylab for his analysis. Through his volunteer work at the Nassau County Medical Center, Stein was permitted to use their laboratory facilities in making his analysis. He carried out some 15 analytical tests on the samples and determined that only two of four samples supplied had survived the repeated reculturing. Of these two, Stein could identify nothing abnormal in the Staphylococcus epidermidis. Tests of the bacteria showed a reaction, but it may have been due to contamination of the sample. Analysis of microbiology samples by the scientists at Johnson Space Center showed no increase in the presence of medically important bacteria throughout the Skylab mission. Even though Stein's original experiment could not be performed, he gained valuable experience in microbiology which has furthered his studies in the field.

Again, Skylab's unique scientific facilities had proven useful as a laboratory for students interested in performing life science experiments at the cellular level in space.


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