MMG301 1nd Edition Lecture 30Outline of Last Lecture I. SoilOutline of Current Lecture II. Animal microbe interactionsCurrent Lecture-Wood contains cellulose (~50%), lignin, and hemicellulose – very low nitrogen content-Obligatory mutual symbiosis: termite completely dependent on its gut microflora to provide its C + N - nutrition derived from anaerobic degradation of the wood particles-Cellulases – enzymes that degrade cellulose, are produced by the termite, by cellulolytic protozoans symbionts, or by ingested cellulase-containing fungi-Some bacteria fix N2 that the termite uses as a nitrogen source-“Lower” termites – populations of protozoans and other microbes in the gut anaerobically degrade cellulose →→ acetate (which is absorbed into termite) and CO2 and H2-Additional populations of anaerobic methanogens and acetogens: CO2 and H2 →→ CH4 and CH3COO-; is a significant global contribution to biological methane production-Plant food sources are extremely difficult to digest-Many herbivores have microbial fermentation chambers to aid this process-Two major classes:-Foregut fermenters (ruminants) – next slide-Hindgut fermenters – contain a cecum between small and large intestine-contains fiber and cellulose-degrading microbes-Sequence of events in food digestion in ruminantsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Food enters rumen where microbes begin anaerobic cellulose digestion2. Mixture goes to omasum and concentrated by water readsorption3. Mixture goes to abomasum (true stomach); acid kills and digests food + microbes4. Next to small intestine for further adsorption of nutrients-Cellulolytic (lysing cellulose) bacteria and protozoa hydrolyze cellulose-Rumen microbe community decomposes the ingested plant material into volatile fatty acids that are absorbed and utilized by the animal, plus gas fermentation products that the animal expels.-Remaining ingested food proceeds to the omasum, abomasum, and intestines for
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