Distribution of cellular amino acids, protein, and total organic nitrogen during fruitbody development in Flammulina velutipes. I. Growth on sawdust medium

Abstract

Dry weights of stipes and pilei of Flammulina velutipes grown on nutrient-supplemented sawdust increased throughout the growth period. The pilei weighed only slightly less than the stipes. Amounts of total organic nitrogen, α-amino nitrogen, and alkali-soluble protein increased in the whole pileus and stipe as the fruitbodies elongated, but the concentrations on a dry weight basis decreased although they were always highest in the pileus. The concentration of alkali-insoluble nitrogen increased in both structures and was highest in the stipe. Concentrations of total nitrogen and protein in surface mycelium did not change significantly when fruitbodies formed but increased markedly when their growth ceased. An average of 8.3 mg dry weight of spores containing about 0.6 mg of nitrogen was released during the life of the fruitbody. Changes in 18 free and 17 protein amino acids were followed quantitatively in the pileus and stipe. Glutamic and aspartic acids and alanine were always among the four predominant free amino acids. Lysine and arginine concentrations remained low in the stipes but increased considerably in the expanding pilei. Ornithine levels increased strongly in the stipe during the early part of rapid elongation but remained almost constant and low in the pilei. Free proline was detected only in traces. Valine became the most abundant protein amino acid during elongation, especially in the stipe. There was very little bound methionine and cystine. In surface mycelium levels of free amino acids were low before fruiting and close to the end of fruitbody growth. Protein amino acids increased during that interval but their proportions remained virtually unchanged and valine was not predominant. The concentration of urea remained very low in both pilei and stipes during their growth.

Changes in nutrient contents of two Nigerian mushrooms, Termitomyces robustus (Beeli) Heim and Lentinus subnudus Berk, during sporophore development

“…Similarly, magnesium, phosphorous and potassium were found to be more preponderant in the pilei than stipes (Tables 2 and 3). These findings are in agreement with those of MOORE et al [lo], and GRUEN et al [4] who found the pileus to be a greater storage depot than the stipe of Coprinus fagopus, Macrolepwta procera and F l a~~u l i~ velutipes. However the observed presence of higher crude fibre and calciumcontents in the stipes of both L. subnudus and T. robustus presumably may be to strengthen the stipe for mechanical support of the pileus (Tables 2 and 3).…”

Effect of sporophore maturity on chemical composition of Volvariella esculenta (Mass) SINGER, a Nigerian mushroom

“…[13] for Macrolepiota proceru, CHANG et al [4] for V. volvacea, GRUEN et al [8] The presence of more food nutrients in the pilei than the stipes is likely to be due to the pileus acting as a strong metabolic force which draws materials continuously from the substrate through the stipe during sporophore development. GRUEN et al [9] found that radioactive materials are moved from the substrate into the pileus through the stipe.…”

Distribution of cellular amino acids, protein, and total organic nitrogen during fruit body development in Flammulina velutipes. II. Growth on potato–glucose solution

“…After sequential extraction with 80% ethanol, ice-cold 5% trichloroacetic acid, and 1 M NaOH, the alkali-soluble protein was measured by the method of Lowry et al (1951) ethanol, hydrolysis of the residue, and purification on resin columns yielded free and protein amino acids, which were analyzed quantitatively with a Technicon TSM-1 R amino acid analyzer. Details of the various procedures were reported previously (Gruen and Wong 1982). For determination of total organic nitrogen in pooled culture medium only small volumes (0.20-0.25 mL) were used for micro-Kjeldahl analysis at each time interval because carbohydrates caused excessive frothing during digestion with H2SO4.…”

“…SFB, VM, and stipes and pilei of LFB (30-day cultures) were freeze-dried and the nitrogenous fractions were extracted and separated as described previously (Gruen and Wong 1982) except that whole fruitbodies and VM were homogenized twice in 10 mL of 80% ethanol for 2 min each with a Soma11 omnimixer. Radiochemically pure L-[U14C]leucine (lot No.…”

“…In the previous report (Gruen and Wong 1982) changes in nitrogenous compounds were followed in fruitbodies of Flarnrnulina velutipes grown on nutrientsupplemented sawdust. Sawdust was the preferred substrate for earlier work in this laboratory on interrelations between pileus and stipe, and is also generally used for commercial cultivation of this species (Tonomura 1978).…”