Screening for carriers of the avian cartilage proteoglycan core protein defect, nanomelia, by denaturing gradient gel electrophoresis.

The avian mutation, nanomelia, is an autosomal recessive embryonic lethal. Homozygous embryos show hypoplasia of the limbs and a parrot-like beak. Biochemical studies have associated this phenotype with the absence of the major cartilage-specific proteoglycan core protein.

The cartilage proteoglycan deficient mutation, nanomelia, contains a DNA polymorphism in the proteoglycan core protein gene that is genetically linked to the nanomelia phenotype.

The avian mutation, nanomelia (nm), is an autosomal recessive embryonic lethal. Homozygous embryos show hypoplasia of the limbs and a parrot-like beak. Biochemical studies have associated this phenotype with the absence of the major cartilage specific proteoglycan core protein (Argraves et al.

Speech development.

Babies are born nonverbal, yet they spontaneously and seemingly effortlessly acquire the complex skills necessary for oral communication. Interestingly, many of these skills have "golden periods" of maximally efficient learning--failure to acquire the skill at that time may lead to speech delay. This article discusses the normal pattern of speech development.

Identification and distribution of a proctolin-like neuropeptide in the nervous system of the gypsy moth, Lymantria dispar, and in other Lepidoptera.

Although the neuropeptide proctolin has important functions in many arthropods, it is reported to be absent in Lepidoptera. Its possible occurrence in these insects was reinvestigated by bioassays of HPLC fractions and immunocytochemistry. A proctolin-like substance was recovered from the frontal and subesophageal ganglia of Lymantria dispar.

The independent synthesis and secretion of cartilage proteoglycan and link protein by embryonic chicken chondrocytes.

The synthesis of cartilage link proteins was studied in organ cultures of sterna from normal and nanomelic chick embryos. Nanomelic chondrocytes synthesize cartilage-specific proteoglycans at 1 to 2% of normal levels, and therefore, nanomelic cartilage contains very little proteoglycan aggregate. The defect in proteoglycan synthesis results from a reduced availability of proteoglycan core protein.