A Symbiotic Blepharisma

During the summer of 1946, while studying material taken from Marble Lake in Dickinson County in Northwest Iowa a Blepharisma, apparently containing zoochlorellae, was observed. Kahl (1932) lists no symbiotic Blepharisma, but describes Blepharisma coeruleum which apparently eats only the alga Tetraspora. Kahl also cites Blepharisma tardum and Blepharisma dileptus as having a diet composed primarily of red bacteria. It was thought an interesting problem would be to determine the relationship between the Blepharisma and green alga thought to be zoochlorella

A Peculiar Staining Reaction in Euglena rubra Hardy 1911

During experimental work in which routine temporary stains were applied to various species of Euglena, an unusual reaction was found to occur in Euglena rubra when subjected to Noland\u27s 1928 stain and fixative

The Cause of the Red-Green Color Change in Euglena Rubra

Euglena rubra is one of the species of Euglena in which a color change from green to red may be produced in a few minutes by the migration of pigment granules from central to peripheral positions. The purpose of the present study was to determine the color of light most effective for bringing about this change. Light sources used were direct sunlight and a 500 watt lamp. The organisms were placed between a glass slide and coverslip, and the color change was observed macrosopically and microscopically. When the experimental arrangement permitted heating of the slide to occur, the time necessary for the change was an inverse function of energy content as measured with a thermopile, regardless of the color of the light employed. This color change could also be produced by heating to about 40° C. in the dark. However, when heating was minimized by placing the slides on ice, blue light was much more effective than longer wavelengths of the same energy content. At low temperatures the end point of the color change was also much sharper than when heating of the slide was permitted. The green-red color change, therefore, may be affected by either of two factors: (1) an increase in temperature produced by either heat or radiant energy, or (2) by visible light, especially of the shorter wavelengths, in the absence of appreciable heating

The Nature of Man as Identified from the Study of the History of Heart and Circulation

Generic man has evidenced curiosity concerning self and the external world since the beginning of recorded history. How is the external world related to man and how does it affect man\u27s nature? Possible answers to these understandings involve both objective and subjective experiences. The objective world can be perceived by others and verified. Similar interpretations are often functions of common environments and educational dogma. Subjective experience is a private matter which may deny communication, or if communicated, may deny common interpretation. It is hoped that primarily through focusing upon objective experiences as recorded in the history of the development of concepts concerning the heart and circulation that some insights into the nature of man may be identified

Protozoa of Iowa

Ten years ago, the authors, while working at the University of Iowa Lakeside Laboratory at Lake Okoboji, compiled a list of Protozoa studied that summer. It was felt such a list could be enlarged upon and become a useful reference for workers in the field of Protozoology. As Protozoa have been identified we have added species from the vicinities of Lakeside Laboratory, Des Moines and Iowa City. Most of these were free living, but we have also included some parasitic forms. In addition we have made some attempt to include those mentioned in readily accessible literature, but no attempt has been made to make an exhaustive survey. We intend to supplement this list with additional forms as they are revealed by an intensive search of published material. We believe that this list is sufficiently complete to be of considerable value in its present form

Relative Mitochondrial Volume in Liver Cells of A/Jax Mice Under Influence of Carbon Tetrachloride

The purpose of this study was to determine the relative volume of mitochondria in situ in hepatic cells adjacent to the interlobular veins in the livers of normal A-Jax mice and of A-Jax mice fed carbon tetrachloride dosages for varying periods of time. The liver tissues were fixed in Regaud\u27s fluid, sectioned at 3 microns, and stained with iron haematoxylin. A procedure developed by Meglitsch et al. was utilized in determining the relative mitochondrial volume of the hepatic cells. The following were determined in the study: (1) normal mice older than six weeks possessed a greater relative mitochondrial volume in both the peripheral and basal regions of the median layer liver lobe than six-week normal mice, and (2) the relative mitochondrial volume of hepatic cells of A/Jax mice fed carbon tetrachloride was significantly less than normal mice of similar age

The 1989 Recommended Pesticide and Nitrogen Use Survey: Description and Policy Applications

The public and the agricultural community are concerned with the impact of agrichemical use on the environment. Of particular concern is the impact of pesticides and nitrogen on the quality of surface and ground waters (Nielson and Lee 1987). Although a national effort is under way to address agricultural contributions to water contamination, lack of data is hindering progress. Data are needed to characterize agrichemical use and its subsequent fate and transport throughout the ecosystem. Reliable data are vital for informed policy decisions weighing the potential risks and benefits (Delwiche 1970). In the absence of that data about total amounts of agrichemicals being used on crops and the rates and methods of application, it is difficult to describe the link between agricultural porduction practices and environmental quality, or to assess the impacts of programs and policies addressing water quality. This report documents the 1989 Recommended Pesticide and Nitrogen Use Survey. The survey was conducted to alleviate part of the data deficiency by collecting detailed information on recommended pesticide and nitrogen uses and application practices in 48 states. Information on usage was obtained by crop, tillage practice, and soil texture. Crops covered in the survey included alfalfa, barley, corn grain, corn silage, cotton oats, pasture, other hay, peanuts, sorghum grain, sorghum silage, soybeans, spring and winter wheat, and sunflowers. Tillage practices included spring and fall plow conventional tillage, conservation tillage, ridge tillage, and no tillage. By providing detailed information on the rate and total amount of agrichemicals applied to the soil surface, the survey provides data for investigating the behavioral and economic links between environmental quality and decision making within agricultural production. In addition, the data can be used in assesing the impacts of policies and porgrams addressing water quality

A Procedure for Determining the Relative Volume of Mitochondria in Hepatic Cells

About forty years ago Cowdry\u27s monograph on mitochondria appeared evaluating the work of previous investigators, indicating synonymy and, in a sense, bringing the first exploratory phase of the study of these cellular constituents to a close (1). Reasonably specific methods for their demonstration had been devised, and it was possible to have some confidence in the conclusions that the so-called mitochondria of different kinds of cells, despite dissimilarities in size or shape, were comparable cellular parts

Some Aspects of Quantitative Histology of the Liver of A-Jax Mice Before and During Tumor Induction with Carbon Tetrachloride

The proportion of the cell populations composed of parenchymal, littoral, and other types of cells is reported for control mice, mice repeatedly anesthetized, mice fed with olive oil repeatedly, and mice fed with carbon tetrachloride and olive oil, showing that the cellular components undergo a marked change when carbon tetrachloride is administered. The proportion of the liver volume occupied by parenchymal cells is found to be relatively stable throughout the period of tumor induction. The nuclear-cytoplasmic ratio of parenchymal cells is found to fall with the aging of control mice and those fed olive oil or anesthetized during the period of the experiment. The nuclear-cytoplasmic ratio is found to fall to a minimal point during the first two weeks of carbon tetrachloride feeding, thereafter gradually rising to normal values for mice of the same age, and eventually rising, after 24 feedings, to a value exceeding that of normal mice of the same age. Between 24 and 30 feedings the nuclear-cytoplasmic ratio undergoes a decrease. The volumes of parenchymal cell nuclei are found to vary with the position in a lobule, the maximal nuclear volumes being found in a region about 100μ to 200μ from the central vein in lobules of average size

DNA, RNA, Lipid Phosphorus, and Acid Soluble Phosphorus in Normal A-Jax Mouse Livers

The concentrations of these substances in wet liver tissue from randomly selected, adult mice were determined colorimetrically. DNA exhibits a modal concentration near 320 mg. per 100 gm. of wet tissue. Cytoplasmic constituents do not exhibit modal concentrations. Preliminary measurements performed upon mice fed carbon tetrachloride in olive oil indicate lower concentrations of RNA, acid soluble phosphates, and lipid phosphates in experimental mice