Glycoconjugate sugar residues in the chick embryo developing lung: a lectin histochemical study
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Published on: September 21, 2012
G Gheri1, E Sgambati, S G Bryk
1Department of Anatomy, Histology and Forensic Medicine, Policlinico di Careggi, Florence, Italy. gheri@dada.it
Insights
This study tracked sugar changes in developing chick lungs using lectins. Specific sugar residues appear on lung cells, coinciding with the onset of breathing.
Area of Science:
- Histochemistry
- Developmental Biology
- Glycobiology
Background:
- Glycoconjugates are crucial for cellular processes.
- Understanding their role in lung development is important.
Purpose of the Study:
- To investigate the distribution and changes of oligosaccharides in chick lung development.
- To correlate sugar residue appearance with lung morphogenesis and respiratory function.
Main Methods:
- Lectin histochemistry using seven horseradish peroxidase-conjugated lectins (PNA, SBA, DBA, WGA, Con A, LTA, UEA I).
- Analysis of lung tissue from chick embryos, 1-day-old chicks, and adult animals.
Main Results:
- Specific sugar residues (D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine, alpha-D-mannose, sialic acid) were identified during lung formation.
- Changes in sugar residue distribution were observed as parabronchi and atria developed.
- The appearance of beta-N-acetyl-D-galactosamine and alpha-D-mannose on air capillary lining cells correlated with the initiation of respiratory activity.
Conclusions:
- Oligosaccharidic components of glycoconjugates play a role in regulating lung morphogenesis.
- The observed changes in sugar residues are linked to the functional maturation of the chick lung and the onset of respiration.
Abstract:
A lectin histochemical study was performed to investigate the distribution and changes of the oligosaccharidic component of the glycoconjugates in the lung of chick embryos, of 1-day-old chick, and of the adult animal. For this purpose, a battery of seven horseradish peroxidase-conjugated lectins (PNA, SBA, DBA, WGA, Con A, LTA, and UEA I) were employed. During the first phase of parabronchi and atria formation, D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine, alpha-D-mannose, and sialic acid, present at the level of the surface and of cytoplasmic granules of the lining epithelial cells, seem to play a role in regulating morphogenetic phenomena. In the subsequent phases, the parabronchial lumen and the atrial cavities were characterized by the presence of lectin-reactive material rich in terminal D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine and alpha-D-mannose. From day 18 onwards and immediately after hatching, the free border of the cells lining the air capillaries was characterized by the presence of beta-N-acetyl-D-galactosamine and alpha-D-mannose. The appearance of these sugar residues was concomitant with the beginning of respiratory activity.
