Organisms Commons^™

A Study Of Water-Soluble Inhibitory Compounds (Algicides) Produced By Fresh-Water Algae, Denny O. Harris, Manhar C. Parekh

KWRRI Research Reports

A complex system of growth inhibitors was observed in the green algae (Volvocaceae). Inhibitors were found in the culture filtrates of some genera which limit their own growth (autoinhibitors) while others in the family produce substances which check the growth of other genera (heteroinhibitors). These inhibitors were destroyed by autoclaving. It was decided that Pandorina morum, which produced the strongest inhibitor and Volvox tertius, the most sensitive to the inhibitor would make an excellent model system for a study of the chemical and physical properties of these naturally occurring algicides. The algicide could be removed from actively growing cultures about …

Phytoplankton Succession In The Lafayette River, Estuary, Norfolk, Virginia, Thomas W. Purcell Lll

Biological Sciences Theses & Dissertations

Abstract unavailable.

Experimentation To Develop Procedures To Be Used In The Investigation Of The Effects Of Restriction On The Unmodified Dna Of The Bacteriophage Lamda, John Haynes

Honors Theses

The results of experimentation approximately twenty years ago with variuos bacteriophages by Ralston and Krueger¹⁶, Anderson and Felix¹, Luria and Human¹², and by Bertani and Weigle² have shown that the host range of a given phage depends directly on the bacterial strain on which the phage has last propagated. This event came to be known as host-induced modification or host-controlled variation. As this phage host range is controlled by the host environment and can be altered from one generation to another it has, according to Luria, made microbiology "the last stronghold of Lamarckism" …

Mitochondrial Activity Of Hardened And Nonhardened Rye (Secale Cereale) Plants Exposed To Freezing Temperatures, Bryce D. Bennett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Five day old dark-grown seedlings of Secale cereale variety "cougar" grown at 20 C were subjected to hardening at 2 C in daily increments from 0 to 7 days, to temperature stress at -5 C for 0, 1, and 3 days, and to recovery at 20 C for 0, 1, and 3 days. Unhardened plants were killed by temperature stress but as the time of hardening increased fewer plants were killed. After 5 days of hardening all plants survived subsequent freezing stress.

Mitochondria were isolated from the plants after they received various combinations of the three temperature treatments. There were …

Ice Nuclei Inventory: Wasatch Weather Modification Experimental Area, William F. Slusser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several large sources of ice nuclei were identified for the Wasatch Weather Modification Experimental Area. When stable air masses remained over the area for several days, ice nuclei concentrations as large as 1750 per liter (measured at -20 C) were found at the surface. Concentrations as large as 6000 per liter were measured with an airborne ice nuclei counter over the smelter industry of the Salt Lake Valley. Ice nuclei concentrations during storm periods were usually less than 3 per liter, indicating an excellent potential for increasing precipitation amounts over the Wasatch Mountains through the release of artificial ice nuclei. …

Proteolytic Enzymes Of Lactic Streptococci And Their Use In Improving Body And Texture Of Direct Acid Cottage Cheese, Gulamnabi Y. Vahora

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Proteolytic activity of Streptococcus cremoris HP, P₂ and AM₂; Streptococcus lactis-C₂, ML₈ and a commercial mixed culture was determined in skimmilk and whey by measuring the increase in Absorbency at 274.5 nm of a pH 4.6 soluble filtrate, following incubation in a 2.5% casein solution. Proteolytic activity, rate of acid production and growth rate decreased in order of C₂, HP, mixed culture, AM₂, ML₈ and P₂ at a regulated pH (6.1 - 6.2) and 32 C. Maximum proteolytic activity for all cultures was found during the stationary …

Potato Variety Trial As A Step Of A Potato Breeding Program, Gonzalo Claure-Vallejo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A potato varietal trial, the equivalent of the final step in a potato breeding and testing program was conducted in 1972 at the Farmington Experimental Sub-station, Farmington, Utah. The test consisted of twelve named varieties and two numbered selections.

This study measured the yielding capacity of new potato varieties and selections during one growing season at one location in Utah. Yields were compared with those of the older accepted varieties grown in the state and used as control or standard varieties in the varietal trial.

This study provided valuable information for growers and processors in determining the suitability of these …