Biochemical changes during larval development of the xanthid crabRhithro panopeus harrisii. II. Nucleic acids

✍ Scribed by S. D. Sulkin; R. P. Morgan; L. L. Minasian

• Publisher: Springer-Verlag
• Year: 1975
• Tongue: English
• Weight: 400 KB
• Volume: 32
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00388504

✦ Synopsis

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) contents were measured daily during the zoeal development of the crab Rhithropanopeus harrisii (Gould). DNA concentration (per unit protein) decreased as larvae increased in size. Total DNA content per larva showed an abrupt increase at the second molt and increased steadily during the third and fourth zoeal stages. Ratios of fresh weight to DNA were highest during the first two zoeal stages, dropped sharply at the second molt, then increased during the third and fourth zoeal stages. RNA:DNA ratios showed cyclical activity apparently related to the molt cycle. Assuming that fresh weight:DNA ratio reflects cell size and that DNA content reflects cell number, growth during the first two stages is due primarily to increase in cell size and during the last two stages to a combination of increase in cell size and number. Assuming further that RNA:DNA ratios reflect protein-synthesis activity, such activity in these larvae follows a rhythm related to the molt cycle.