Bacteroides amylophilus has growth requirements for Na+, PO43-, K+, and small quantities of Mg2+. No requirement could be shown for Ca2+ in media previously found growth-yield-limiting for Bacteroides succinogenes. Deletion of Co2+, Mn2+, Cl-, or SO42 did not affect growth. Quantitative studies indicate that Na+, K+, and PO43have differing effects on the growth of B. amylophilus. A concentration of sodium and potassium ions affects both growth rate and growth yield, whereas a phosphate concentration markedly affects growth yield, but affects growth rate only slightly, if at all. The sodium requirement of B. amylophilus is absolute. It cannot be replaced by K+, Li+, Rb+, or Cs+. The latter three monovalent cations are toxic to B. amylophilus if supplied to the organism at Na+-replacing concentrations. K+ is inactive at similar concentrations. The K+ requirement of B. amylophilus may be satisfied by Rb+. The concentration of Na+ required by B. amylophilus for abundant growth suggests that B. amylophilus should be considered a slightly halophilic organism. The results suggest that Na+ may be a more frequent requirement among terrestial bacteria obtained from relatively low-salt environments than has been previously believed. . Strains were maintained by periodical loop transfer in the rumen fluid, glucose, cellobiose, agar (RGCA) medium of Bryant and Burkey (7) as modified by Bryant and Robinson (8). The morphological and general biochemical characteristics of all strains used were previously shown (10) to agree with the original species description of Bacteroides amylophilus (15). 782on August 5, 2020 by guest http://jb.asm.org/ Downloaded fromEffect of magnesium and sulfur on cellulose digestion of purified rations by cattle and sheep.

Mechanical EngineeringSolar power generation deployment is increasing globally with photovoltaic modules.Most energy available to conventional PV is absorbed as heat or passes through.

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