Microorganisms of the Upper Atmosphere: III. Relationship between Altitude and Micropopulation

Simultaneous sampling for microorganisms was accomplished at altitudes of 690, 1,600, and 3,127 meters. The location of temperature inversions in relation to the collection altitude determined, to a great extent, the micropopulation. High micropopulations were found when an inversion was above the sampling altitude, and low populations when the inversion was below the sampling altitude. Diurnal periodicity which could be generally correlated with periods of minimal and maximal convective activity was observed. Evidence is presented showing that the micropopulation is more stable at higher altitudes than at lower altitudes.     

Microorganisms of the Upper Atmosphere: V. Relationship between Frontal Activity and the Micropopulation at Altitude

The relationship between frontal activity and the micropopulation of the atmosphere at altitude is described. It is shown that certain of the meteorological events associated with frontal activity quantitatively modify the micropopulation of the atmosphere. Precipitation associated with frontal passage reduces the micropopulation at altitude, whereas frontal activity with high levels of associated surface and atmospheric turbulence results in great increases in micropopulations of the upper atmosphere-particularly in those situations where surface conditions are conductive to the development of dust.     

Microorganisms of the Upper Atmosphere: II. Microorganisms in Two Types of Air Masses at 690 Meters over a City

The viable micropopulation found, at altitude over a city, in a land air mass was significantly higher than that found in a marine-influenced air mass. The percentage distribution of bacteria and fungi was approximately equal in both types of air masses. This indicates that, under the conditions of the experiment, the marine air mass was influenced by the land area over which it traveled during passage from its source to the sampling area. Activities taking place within the city significantly increased the micropopulation at altitude. This increase was quantitatively so small that it was not identifiable when the micropopulation moving into the city was high-as in a land air mass-but was recognizable when the micropopulation was low-as in a marine-influenced air mass. The modification of the micropopulation at altitude by temperature inversions was shown.     

Microorganisms of the Upper Atmosphere: IV. Microorganisms of a Land Air Mass as It Traverses an Ocean

The viable micropopulation at three altitudes (152, 1,066, and 1,981 meters) of a land air mass as it traversed an ocean was determined. At the low altitude, a consistent pattern of decrease in numbers of land-originating microorganisms with increasing distance from shore was observed. At the higher altitudes, the observed pattern was one of irregularity. At the lower altitude the percentages of bacteria and fungi were approximately equal near the coast, but as distance from the coast increased, fungi predominated over the bacteria at all sampling locations. The greatest number of different genera of both bacteria and fungi were obtained at or near the coast. Fungi of the genera Alternaria, Hormodendron, Penicillium, and Aspergillus, and bacteria of the genera Micrococcus and Bacterium predominated at all altitudes and locations.     

Terrestrial Microorganisms at an Altitude of 20,000 m in Earth's Atmosphere

A joint effort between the U.S. Geological Survey's (USGS) Global Desert Dust and NASA's Stratospheric and Cosmic Dust Programs identified culturable microbes from an air sample collected at an altitude of 20,000 m. A total of 4 fungal (Penicillium sp.) and 71 bacteria colony-forming units (70 colonies of Bacillus luciferensis believed to have originated from a single cell collected at altitude and one colony ofBacillus sphaericus) were enumerated, isolated and identified using a morphological key and 16S rDNA sequencing respectively. All of the isolates identified were spore-forming pigmented fungi or bacteria of terrestrial origin and demonstrate that the presence of viable microorganisms in Earth's upper atmosphere may not be uncommon.     

Sampling Techniques for the Enumeration of Microorganisms in the Diverticulum of the Anterior Thoracic Air Sac of Chickens

The swab, excise, flush, and agar microbial sampling techniques were applied randomly to the air sac cavities of 130 healthy broiler chickens of 56 to 70 days of age when slaughtered. Samples were obtained from both nonscalded and scalded chickens. The scalded chickens were immersed in the scald water (49 ± 0.5 C) for 120 sec immediately after severing the blood vessels from the outside at the base of the lower mandible. From these data, a selection was made of a sampling technique for the air sac cavity which would yield reproducible counts with the least amount of variation.

The flush and swab technique did not differ significantly and had less variation than did the excise and agar techniques. Even though no significant differences existed between the flush and swab techniques, the flush technique might be preferred because of the closed system present during the time in which the sample is obtained. The method of expressing microbial concentration in the air sac cavity might best be as “per air sac.”

     

Measurment of pedal loading in bicycling: I. Instrumentation

This paper presents a new instrumentation system to precisely measure pedal loads and pedal position. A pedal/dynamometer unit implementing four octagonal strain rings measures all six load components between the foot and pedal. To study the relationship between foot position and loading, the pedal/dynamometer offers three degree-of-freedom adjustability. Pedal position along the pedal arc is precisely described by measuring crank arm angle and relative angle between pedal and crank arm. Linear, continuous rotation potentiometers measure the two angles. Transducer signals are sampled by a digital computer which calculates resultant loads and pedal position as functions of crank arm angle. Transducers are designed to mount on most bicycles without modification. Test subjects ride their own bicycles unconstrained on rollers so that loading data is representative of actual cycling.     

Microorganisms of the San Francisco Sour Dough Bread Process: I. Yeasts Responsible for the Leavening Action

Two hundred isolates from San Francisco sour dough French bread fermentations (40 from each of five different bakeries) were screened by fermentation tests and for their ability to grow in the presence of cycloheximide (Actidione). All of the isolates from four of the bakeries and 70% of those from the fifth were unable to utilize maltose but grew well on other sugars, even in the presence of cycloheximide. The remaining few isolates from the fifth bakery utilized maltose but not galactose and were inhibited by cycloheximide. No bakers' yeast types were found. Sixteen of the maltose-negative and five of the galactose-negative isolates were subjected to more rigorous taxonomic procedures. All of the maltose-negative isolates were identified as asporogenous strains of Saccharomyces exiguus (Torulopsis holmii) and the galactose-negative ones, as S. inusitatus. The predominance of S. exiguus, its vigor in the particular acidic environment of the sour dough, and the correlation of its numbers with the leavening function constitute strong evidence on the role of this organism in the sour dough system.     

Function of Growth Factors for Rumen Microorganisms I. Nutritional Characteristics of Selenomonas ruminantium

Nutritional characteristics of Selenomonas ruminantium var. lactilytica isolated from a sheep rumen were studied. The organism required for growth the addition of a clarified rumen fluid to a Trypticase-yeast extract medium with either lactate or glucose as an energy source. The requirement for rumen fluid was found to be satisfied by volatile fatty acids in glucose media and by biotin in lactate media. Straight-chain saturated fatty acids with C(3) to C(10) carbon skeleton had been found to be effective. Among them, n-valerate was most effective at the lowest concentration. An abnormal morphology was observed with n-valerate-deficient glucose media. n-Valerate was essential in glucose media, and it was stimulatory in lactate media. Fermentation products from glucose were lactate, propionate, and acetate, and fermentation products from lactate were propionate and acetate. When cells were grown in a glucose medium containing n-valerate-C(14), the label was present in cell fractions. Almost all of the activity was found in lipid materials.     

Inexpensive Device for the Aerobic and Anaerobic Sampling of Microorganisms in Lake and Shallow Ocean Waters

An inexpensive device suitable for sampling microorganisms in water and easily constructed from readily available laboratory equipment is described. The need to transfer subsamples to culturing flasks after collection is eliminated by partly filling the sampling vessels with growth medium prior to sampling. The device is readily adapted for sampling different volumes, is simple and quick to operate, and is suitable for use with prereduced media. Contamination from layers other than that being sampled is insignificant.     

Life at the dry edge: Microorganisms of the Atacama Desert

The Atacama Desert, located in northern Chile, is the driest and oldest Desert on Earth. Research aimed at the understanding of this unique habitat and its diverse microbial ecosystems begun only a few decades ago, mainly driven by NASA's astrobiology program. A milestone in these efforts was a paper published in 2003, when the Atacama was shown to be a proper model of Mars. From then on, studies have been focused to examine every possible niche suitable for microbial life in this extreme environment. Habitats as different as the underside of quartz rocks, fumaroles at the Andes Mountains, the inside of halite evaporates and caves of the Coastal Range, among others, have shown that life has found ingenious ways to adapt to extreme conditions such as low water availability, high salt concentration and intense UV radiation.