Asparagine: A host chemical essential for the growth and development of Eucelatoria bryani, a tachinid parasitoid of Heliothis SPP

In vitro rearing of parasitoids: Role of host factors in nutrition

“…Occasionally adult yields reach 70% or higher (Nettles, unreported data). When aspartic acid replaced asparagine in the amino acid mixture, no pupae and no adults were obtained [15]. These data demonstrate that E. bryani larvae are unable to convert aspartic acid to asparagine at a significant rate and that asparagine synthetase either is missing or is present at exceptionally low levels in the parasitoids.…”

“…There were several reasons for doing so, but the most important was that asparagine is more water soluble than aspartic acid. Asparagine is an essential component of artificial diets for E. bryuni larvae, host hemolymph contains greater quantities of asparagine than of aspartic acid (Nettles and Holman, unreported data), and free amino acids have striking effects on growth of E. bryuni [14,15].…”

“…In the presence of 1.83% total free amino acids and 2.6% soy flour, yields were much higher, and 50% and 28% of E. bryani developed to the pupal and adult stages, respectively [14]. When each of the 10 essential amino acids and asparagine were deleted from diets containing 1.83% total free amino acids and 2.6% soy flour, most of the E. brydni larvae died in the second instart and very few insects developed beyond the third instar [14,15].…”

“…€. bryani larvae apparently digest proteins slowly because growth is extremely poor and death results when free amino acids are deleted from a protein-rich medium [14,15]. Although the amino acids essential for E. bryuni are obtained from plant proteins ingested by the host, free amino acids in a sense are host factors for E .…”

“…The best evidence that a parasitoid species is dependent on a host factor comes from E. bryuni research. Asparagine is an essential dietary ingredient for E. bryuni larvae, and, if aspartic acid is converted to asparagine at all, it obviously is not metabolized at a rate adequate to meet the demands of the rapidly developing larva [15]. Because sizable quantities of asparagine are present in host hemolymph (Nettles and Holman, unreported data), the genetic change that resulted in the loss or in a lower level of asparagine synthetase was harmless in vivo and was retained because there presumably was no selection against this trait.…”

In vitro rearing of parasitoids: Role of host factors in nutrition

“…Occasionally adult yields reach 70% or higher (Nettles, unreported data). When aspartic acid replaced asparagine in the amino acid mixture, no pupae and no adults were obtained [15]. These data demonstrate that E. bryani larvae are unable to convert aspartic acid to asparagine at a significant rate and that asparagine synthetase either is missing or is present at exceptionally low levels in the parasitoids.…”

“…There were several reasons for doing so, but the most important was that asparagine is more water soluble than aspartic acid. Asparagine is an essential component of artificial diets for E. bryuni larvae, host hemolymph contains greater quantities of asparagine than of aspartic acid (Nettles and Holman, unreported data), and free amino acids have striking effects on growth of E. bryuni [14,15].…”

“…In the presence of 1.83% total free amino acids and 2.6% soy flour, yields were much higher, and 50% and 28% of E. bryani developed to the pupal and adult stages, respectively [14]. When each of the 10 essential amino acids and asparagine were deleted from diets containing 1.83% total free amino acids and 2.6% soy flour, most of the E. brydni larvae died in the second instart and very few insects developed beyond the third instar [14,15].…”

“…€. bryani larvae apparently digest proteins slowly because growth is extremely poor and death results when free amino acids are deleted from a protein-rich medium [14,15]. Although the amino acids essential for E. bryuni are obtained from plant proteins ingested by the host, free amino acids in a sense are host factors for E .…”

“…The best evidence that a parasitoid species is dependent on a host factor comes from E. bryuni research. Asparagine is an essential dietary ingredient for E. bryuni larvae, and, if aspartic acid is converted to asparagine at all, it obviously is not metabolized at a rate adequate to meet the demands of the rapidly developing larva [15]. Because sizable quantities of asparagine are present in host hemolymph (Nettles and Holman, unreported data), the genetic change that resulted in the loss or in a lower level of asparagine synthetase was harmless in vivo and was retained because there presumably was no selection against this trait.…”

In vitro rearing of parasitoids: Role of host factors in nutrition

“…Occasionally adult yields reach 70% or higher (Nettles, unreported data). When aspartic acid replaced asparagine in the amino acid mixture, no pupae and no adults were obtained [15]. These data demonstrate that E. bryani larvae are unable to convert aspartic acid to asparagine at a significant rate and that asparagine synthetase either is missing or is present at exceptionally low levels in the parasitoids.…”

“…There were several reasons for doing so, but the most important was that asparagine is more water soluble than aspartic acid. Asparagine is an essential component of artificial diets for E. bryuni larvae, host hemolymph contains greater quantities of asparagine than of aspartic acid (Nettles and Holman, unreported data), and free amino acids have striking effects on growth of E. bryuni [14,15].…”

“…In the presence of 1.83% total free amino acids and 2.6% soy flour, yields were much higher, and 50% and 28% of E. bryani developed to the pupal and adult stages, respectively [14]. When each of the 10 essential amino acids and asparagine were deleted from diets containing 1.83% total free amino acids and 2.6% soy flour, most of the E. brydni larvae died in the second instart and very few insects developed beyond the third instar [14,15].…”

“…€. bryani larvae apparently digest proteins slowly because growth is extremely poor and death results when free amino acids are deleted from a protein-rich medium [14,15]. Although the amino acids essential for E. bryuni are obtained from plant proteins ingested by the host, free amino acids in a sense are host factors for E .…”

“…The best evidence that a parasitoid species is dependent on a host factor comes from E. bryuni research. Asparagine is an essential dietary ingredient for E. bryuni larvae, and, if aspartic acid is converted to asparagine at all, it obviously is not metabolized at a rate adequate to meet the demands of the rapidly developing larva [15]. Because sizable quantities of asparagine are present in host hemolymph (Nettles and Holman, unreported data), the genetic change that resulted in the loss or in a lower level of asparagine synthetase was harmless in vivo and was retained because there presumably was no selection against this trait.…”

In vitro rearing of parasitoids: Role of host factors in nutrition

“…Occasionally adult yields reach 70% or higher (Nettles, unreported data). When aspartic acid replaced asparagine in the amino acid mixture, no pupae and no adults were obtained [15]. These data demonstrate that E. bryani larvae are unable to convert aspartic acid to asparagine at a significant rate and that asparagine synthetase either is missing or is present at exceptionally low levels in the parasitoids.…”

“…There were several reasons for doing so, but the most important was that asparagine is more water soluble than aspartic acid. Asparagine is an essential component of artificial diets for E. bryuni larvae, host hemolymph contains greater quantities of asparagine than of aspartic acid (Nettles and Holman, unreported data), and free amino acids have striking effects on growth of E. bryuni [14,15].…”

“…In the presence of 1.83% total free amino acids and 2.6% soy flour, yields were much higher, and 50% and 28% of E. bryani developed to the pupal and adult stages, respectively [14]. When each of the 10 essential amino acids and asparagine were deleted from diets containing 1.83% total free amino acids and 2.6% soy flour, most of the E. brydni larvae died in the second instart and very few insects developed beyond the third instar [14,15].…”

“…€. bryani larvae apparently digest proteins slowly because growth is extremely poor and death results when free amino acids are deleted from a protein-rich medium [14,15]. Although the amino acids essential for E. bryuni are obtained from plant proteins ingested by the host, free amino acids in a sense are host factors for E .…”

“…The best evidence that a parasitoid species is dependent on a host factor comes from E. bryuni research. Asparagine is an essential dietary ingredient for E. bryuni larvae, and, if aspartic acid is converted to asparagine at all, it obviously is not metabolized at a rate adequate to meet the demands of the rapidly developing larva [15]. Because sizable quantities of asparagine are present in host hemolymph (Nettles and Holman, unreported data), the genetic change that resulted in the loss or in a lower level of asparagine synthetase was harmless in vivo and was retained because there presumably was no selection against this trait.…”