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L W Olson

Publications and source records attributed to L W Olson.

At least 19 recordsLinked to original sources
PubMed1996

Methodology for adjusting scrotal circumference to 365 or 452 days of age and correlations of scrotal circumference with growth traits in beef bulls.

A retrospective analysis was conducted on data collected from 1983 through 1991, where weight and hip height were measured at start of test and every 28 d on 604 bulls completing a 224-d forage-based gain test. Scrotal circumference (SC) was measured at start of test, and at either end of test or end of the weigh period after individual bulls reached 365 d of age. Over 3 yr of this study, SC was additionally measured every 28 d. Bulls were representatives of 5 breed groups: Angus, Santa Gertrudis, Simmental, Continental (predominantly Charolais), and Zebu (predominantly Simbrah). Adjusted 365-d SC and adjusted 452-d SC were calculated by regression analysis and from formulas based on SC growth of individuals to 140 and 224 d on test, respectively. Breed group differences were observed for age of dam, birth weight, hip height, weight per day of age, average daily gain and SC at start of test, 140 d, and end of test (224 d). Scrotal circumference was positively correlated with all growth traits. Scrotal circumference was related to breed group, age, weight, hip height, average daily gain, weight per day of age, age by year, and age-by-breed group (P<0.05), as determined by regression analysis. However, omitting weight, hip height, average daily gain, and weight per day of age from the regression model did not significantly affect R2 value. Scrotal circumference growth was linear to 140 d on test; however, SC growth to 224 d on test was curvilinear. The 365-d SC predicted from the formula and from regression analysis differed for Simmental and Zebu by 0.3 and 0.4 cm, respectively (P<0.05). The 452-d SC differed for Santa Gertrudis and Zebu by 0.5 and 0.6 cm, respectively (P<0.05). Formulas based on SC growth of individuals are reasonably accurate predictors of SC at 365 and 452 d of age, when compared with more complex regression analysis. Basing SC adjustments on individual growth appears to account for variables known to affect yearling SC.

Journal Article↗
PubMed1983

Respiration of Gametangia of the Aquatic Phycomycete Allomyces macrogynus: Inhibition by Cyanide or Antimycin and Salicylhydroxamic Acid or Propyl Gallate.

Gametangia of the aquatic phycomycete Allomyces macrogynus have a cyanide- and antimycin A-insensitive respiration, which is sensitive to salicylhydroxamic acid (alternative respiration). Propyl gallate is also an inhibitor of this alternative pathway, and propyl gallate is more efficient than hydroxamic acid. Gametangial respiration is insensitive to propyl gallate, but propyl gallate sensitivity is gradually established when the gametangia are titrated with cyanide. Carbonyl cyanide m-chlorophenyl hydrazone stimulates the cyanide-sensitive respiration and engages the alternative sensitive respiration. Sodium azide inhibits both the alternative and the cyanide-sensitive respiration, but the cyanide-sensitive respiration is inhibited 10 times more efficiently than the alternative respiration. Rotenone inhibits the total respiration and the propyl gallate-insensitive respiration by 33% and the cyanide-insensitive respiration by 43%.The kinetic results reported here are discussed with respect to the models of de Troostembergh and Nyns (1977 Arch Int Physiol Biochem 85:404-406; 1978 Eur J Biochem 53:423-432) and of Bahr and Bonner (1973 J Biol Chem 248:3446-3450) for the partitioning of electrons between cyanide-insensitive and propyl gallate-insensitive respiration. The results reported here do not agree with the model of de Troostembergh and Nyns.

Journal Article↗
PubMed1978

Meiotic recombination and synaptonemal complexes in Saccharomyces cerevisiae.

The course of meiotic recombination, gene conversion and crossing-over, was investigated in Saccharomyces cerevisiae. Gene conversion was used as the selected event by removing cells from a medium inducing and promoting meiosis to a vegetative growth medium selective for convertants. Gene conversion started to increase at the same time as DNA synthesis, and nuclei entered a phase where the chromatin appeared as thread-like structures. Crossing over of linked and unlinked markers also started early but remained at a low level until synaptonemal complexes were formed. However, gene conversion and a limited amount of crossing-over could be completed without synaptonemal complexes. It was concluded that meiotic recombination in yeast can occur as early as during DNA synthesis and does not require the function of synaptonemal complexes. Moreover, the low incidence of crossing-over early in meiosis is attributed to a low frequency of strand isomerization.

Alleles↗
PubMed1978

Mitotic recombination in the absence of synaptonemal complexes in Saccharomyces cerevisiae.

Mitotic cells of a diploid strain of Saccharomyces cerevisiae with appropriate markers for the detection of mitotic crossing-over and mitotic gene conversion were irradiated with X-rays. Induction of these recombinational events was strong. After irradiation, cells were incubated in a rich growth medium and samples were removed for studying the possible formation of synaptonemal complexes up to a time when most cells had completed the first post-irradiation cell division. No complexes were found during the entire period of sampling, during which mitotic recombination in G1 (mitotic gene conversion), DNA replication and G2 (mitotic crossing-over) had occurred. These results are interpreted to mean that synaptonemal complexes are not required for mitotic recombination.

Alleles↗
PubMed1975

The synaptonemal complex and the spindle plaque during meiosis in yeast.

Meiosis in Saccharomyces cerevisiae proceeds principally in the same manner as in other Ascomycetes. Leptotene is characterized by unpaired lateral components and pachytene by the presence of extensive synaptonemal complexes. The synaptonemal complex has the same dimensions and is similar in structure to those described for other organisms. Chromosome counts can now be made by reconstructing the synaptonemal complexes. Diplotene nuclei consistently contain a single polycomplex. The behaviour, doubling and the fine structure of the spindle plaque provide additional markers for the different stages of meiosis.

Cell Nucleolus↗