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Isolation, Identification, and Studies on the Metabolism of Rumen Micro-Organism Growth Factors Present in Natural Materials

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Isolation, Identification, and Studies on the Metabolism of Rumen Micro-Organism Growth Factors Present in Natural Materials ISOLATION, IDENTIFICATION, AND STUDIES ON THE METABOLISM OF RUMEN MICRO-ORGANISM GROWTH FACTORS PRESENT IN NATURAL MATERIALS DISSERTATION Presented In Partial Fuirillraent of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By BURK ALLYN DEHOR ITT, A.B., M.S. The Ohio State University 1957 Approved by: Adviser Department of Agricultural Biochemistry ACKNOWLEDGMENTS I would like to express ray deepest appreciation to Dr. Alvin L. Moxon and Dr. Orville G. Bentley for their guidance and many helpful suggestions during the per­ formance of ray research work. Their interest and leader­ ship is gratefully acknowledged. The timely suggestions and interest of Dr. Ronald R. Johnson are greatly appreciated, in addition to his aid in the preparation of Figures 10, 11, and 12. Appreciation is also extended to the Ohio Agricultural Experiment Station for providing facilities and financial assistance during the course of this work. I am indebted to ray wife for her unceasing encour­ agement and cheerfulness throughout the performance of this work, and her aid in the preparation of this manu­ script. ii TABLE OP CONTENTS General Introduction Part I: Isolation and .identification of Compounds Prom Autolyzed Yeast, Alfalfa Ileal, and Casoin iiydrolysa.te wit h. Cellulolytic Factor Activity for Rumen Micro-organisms In Vitro Literature Review Experimental Procedures In Vitro Rumen ^Fermentation Technique Fractionation Procedures Dowex - 50 I o n Exchange Resin Charcoal Treatment Preparative Scale Paper Chromatography Elution of the Chromatograms Chromatographic Identification of Amino Acids Results Autolyzed Yeast Casein Rydrolysate Alfalfa Extract Known Amino Acids Substrate Level Studies Additive Effects Discussion Summary Part II: Studies on the Metabolism of the isolated Growth Factors (Valine, Proline, Leucine, and Isoleucine) Literature Review Experimental Procedures Amino Acid Analysis In Vitro Rumen Fermentation Technique Using Valine-l-Clh Determination of «<-KetoisovalerIc Acid Results Investigation of Added Amino Acids Rumen Fermentation (In Vitro) with Valine-l-dU Isolation of Radioactive -Ketoisovaleric Acid Cellulolytic Factor Activity of Possible Intermediates in Valine, Proline, and Leucine Metabolism Discussion Summary Literature Cited LIST OP TABLES Table No. Page No 1 * Composition of the Basal Medium Used for the ill Vitro Rumen Fermentation 13 2. Cellulolytic Factor Activity of the C.F. of D - 50 Eluate of Autolyzed Yeast After Separation by Paper Chromato­ graphy with Q0% Phenol 21 3. Cellulolytic/ Factor Activity of the Separated Components From T.P.P.C. of Autolyzed Yeast 2l± If.. Cellulolytic Factor Activity of Casein Hydrolysate and the T.P.P.C. Prepared From Casein Hydrolysate 27 5. Cellulolytic Factor Activity of the Fractions Obtained from Alfalfa Extract #1 by Treatment with Dowex - 50 30 6. Cellulolytic Factor Activity of the Amino Acids Valine, Proline, the Leucines and y-aminobutyric Acid at Varying Levels; Studies on the Additive Effects of These Amino Acids 35 7. The Additive Effect of the Cellulolytic Factor Activity of Valeric Acid, the Amino Acids and Yeast Extract I4.0 8. Study on the Additive Effect of Valeric Acid with Valine and Proline if.2 9. Amino Acid Composition of Fermentation Mixtures 62 10. Cellulolytic Factor Activity of D-Valine, DL-Valine and L-Valine Alone and In Combination with L-Proline 65 11. Amino Acid Composition of Fermentation Mixtures 66 12. Decarboxylation of DL-Valine-l-ClU by Rumen Micro-organisms In Vitro 69 v vi Table TTo. Page No. 13. Relationship of L-Valine andcw-betoiso­ valeric Acid in the in Vitro Rumen Fomentation 80 lij. Cellulolytic Factor Activity of Proposed Intermediates in the Metabolism of Valine and Proline 82 15. Cellulolytic Factor Activity of Proposed Intermediates in the Metabolism of Leucine and Proline 81j. 16. Time Study of Valine and Leucine Plus Proline Versus Isobutyric Acid and Isovaleric Acid Plus 5 -Aminovaleric Acid 86 17. The Cellulolytic Factor Activity of Ornithine 88 LIST OF FIGURES Figure No. Page No. 1. Diagrammatic representation of the chromato­ grams obtained by preparative scale paper chromatography 17 2. The cellulolytic factor activity in vitro of yeast extract and the fractions pre­ pared from this extract 20 3. Diagrammatic sketch of the chromatographic separation of the amino acids from yeast extract In the top portion of the phenol chromatogram (T.P.P.C.) 22 ll. The cellulolytic factor activity in vitro of hydrolyzed casein and the fractions of hydrolyzed casein prepared by large scale paper chromatography 28 p. The cellulolytic factor activity in vitro of alfalfa extract # 2 , and the prepared fractions from this extract 3 1 6 . The cellulolytic factor activity in vitro of the charcoal filtrate of Dowex - £6 eluate of alfalfa extract # 2 and the fractions of this filtrate prepared by large scale paper chromatography 32 7. The cellulolytic factor activity in vitro of the amino acids valine and proline 3k 8 . Additive effects of the amino acids valine, proline, the leucines and Y-aminobutyric acid as cellulolytic factors in vitro 37 9. The effects of varying cellulose substrate levels upon cellulose digestion in vitro 3 9 10. Diagrammatic separation of the amino acids from flasks with added valine and proline determined at 1 3 , 2l± and 30 hours, and of proline, determined at 13 hours 67 vii v i . i l Figure Wo. Page No. 1 1 . Tracings of the chromatographic separation of the 2 , l^-dini trophenylhydrazine deriva­ tives obtained from a fermentation with DL-valine-l-ClU, and the corresponding graph of its radioactivity as measured with a gas-flow chromatographic scanner 77 12. Proposed pathways in the metabolic breakdown of valine and proline 90 H’i General Introduction The significance of rumen micro-organisms, in the utilization of cellulose and other carbohydrates as energy sources by cattle and sheep, was first recognized at about the turn of the twentieth century. As the role of these micro-organisms became better understood, the relationship between their nutritional status and their ability to digest cellulose, synthesize vitamins, and convert non­ protein nitrogen to protein nitrogen became of both prac­ tical and academic interest. Of primary interest, was the determination of the nutritional requirements of this mix­ ed microbial population. Studies at the Ohio agricultural Experiment Station on crude fiber and cellulose digestion in vivo, suggested that certain natural feedstuffs supplied unknown nutri­ ents or growth factors which are essential for cellulose digestion by rumen micro-organisms. This led to the development of an artificial rumen technique, whereby the rumen micro-organisms were cultured in vitro under simulat­ ed rumen conditions. The experimental results obtained by this technique correlated well with previous in vivo results, hence a major contribution had been made toward the determination of the nutritional requirements of these microorganisms. A number of excellent preliminary studies were performed on the quality of roughages, urea utiliza- 1 2 tion, mineral requirements, and the ability of certain natural feedstuffs to enhance the digestion of purified cellulose. As the major nutritional requirements of the rumen bacteria became known, these nutrients were added to the basal medium used for culturing the micro-organisms. The problem soon narrowed itself to the point where the major­ ity of the nutritional requirements of these micro-organisms had been established, except that the rumen micro-organisms required an unknown nutritional factor or factors before any marked degree of cellulose digestion was obtained. These unknown cellulolytic factors , present in the supernatant of rumen juice, were investigated over a period of several years in this laboratory before their identity was estab­ lished. However, subsequent experiments revealed that these cellulolytic factors were not identical to those responsible for the activity of yeast extract and other natural materials. Hence, the occurrence of other unknown compounds capable of stimulating cellulose digestion by rumen micro-organisms was established, and the experimental studies reported herein are concerned with the identifica­ tion of these cellulolytic factors. 1. Throughout this dissertation, the term cellulolytic factor will be used to designate any material or compound which possesses the ability to enhance the digestion of cellulose by rumen micro-organisms in vitro. Part I Isolation and Identification of Compounds From Autolyzed Yeast. AlfalfaT'Meal, and Casein' Hydrolysate with Cellulolytic factor Activity For Rumen Micro-"" orff&ni'ams In Vitro Literature Review The existence of specific nutritional factors supplied by natural feedstuffs, which are required by rumen bacteria for the efficient digestion of cellulose, I'ras first postulat­ ed by Burroughs £t al^ (li|) in 191+9. The results of his in vivo roughage digestion trials (1 1 ; 1 2 ,* 1 3 ;111) indicated that these factors are associated in nature with roughages and protein-rich feeds. In one study (11), rumen bacterial counts were made, and bacterial numbers were observed to increase in direct proportion to roughage digestion, in an effort to gain more detailed information on the factors in­ volved in roughage digestion by rumen micro-organisms,, an in vitro artificial rumen technique was developed by Burroughs (1 0 ), somewhat similar to that described by Marston (ipO). The objective of this study was to culture the rumen
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