Concept explainers
Imagine that you have discovered a new animal that consumes only grass in its diet. You suspect it to be a ruminant and have available a specimen for anatomical inspection. If this animal is a ruminant, describe the position and basic components of the digestive tract you would expect to find and any key microorganisms and substances you might look for. What
To describe:
The position as well as the basic components of the digestive system that would you expect and to find the key microorganism or substances which could look for in this system. The metabolic types of microbes or predicted specific genes that would be present.
Introduction:
Ruminants are herbivorous mammalian animals. The rumen is the specialized digestive organ that is present in the ruminant animals. These animals obtain nutrients from a plant based food or plants as such. Cattle, sheep, goats, camels, and buffalos are examples of the ruminant animals.
Explanation of Solution
The digestive system of ruminants is completely different from those of humans. Before the digestion, the plant based food undergoes fermentation by microbial action. Ruminant animals contain four chambers of the stomach. These chambers are rumen, reticulum, omasum, and abomasum. Intestine is present next to this chamber. The reticulo-rumen present in the alimentary canal, lies before the stomach. If the herbivore animal is non-ruminant then the cecum will lie between the small and the large intestine. For example, horse and rabbit.
The key microbes that are expected to be present are Methanobacterium ruminantium, Bacteroides succinogenes, and Peptostreptococcus elsdenii. The major compounds that would be seen in the rumen are the products of gaseous fermentation such as carbon dioxide, fatty acids (volatile in nature) and methane. The resident microbes that metabolize or ferment key substances in the rumen are fermenters of cellulose sugars and methane. As these microbes are present, the genes that would be expected are genes encoding glycolytic enzymes (cellulases), enzymes of pentose phosphate pathway, coenzymes carbon monoxide dehydrogenase, methyl reductase, and hydrogenases.
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Chapter 23 Solutions
Brock Biology of Microorganisms
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