Synthesis of novel MMT/acyl-protected nucleo alanine monomers for the preparation of DNA/alanyl-PNA chimeras

Alanyl-peptide nucleic acid (alanyl-PNA)/DNA chimeras are oligomers envisaged to be beneficial in efficient DNA diagnostics based on an improved molecular beacon concept. A synthesis of alanyl-PNA/DNA chimera can be based on the solid phase assembly of the oligomer with mixed oligonucleotide/peptide backbone under DNA synthesis conditions, in which the nucleotides are introduced as phosphoramidites, whereas the nucleo amino acids make use of the acid labile monomethoxytrityl (MMT) group for temporary protection of the α-amino groups and acyl protecting groups for the exocyclic amino functions of the nucleobases. In this work, we realized for the first time the synthesis of all four MMT/acyl-protected nucleo alanines, achieved by deprotection/reprotection of the newly synthesized Boc/acyl intermediates, useful monomers for the obtainment of (alanyl-PNA)/DNA chimeras by conditions fully compatible with the standard phosphoramidite DNA synthesis strategy

The postnatal development of masera's organ in the rat

Growth and fine-structural postnatal development of Masera's organ (MO) in the rat was studied. As with the olfactory epithelium proper (OEP) on the nasal septum, the area covered by MO increases during the first 3 weeks of life. The rate of increase in area of MO is the same as for the OEP on the nasal septum. Concomitant with the increase in overall area of MO, the complexity of the free neuroepithelial surface of MO increases. There is an increase in both the number of sensory cilia of receptor cells and microvilli of supporting cells. At 14 days and after sensory cilia are further characterized by the development of a thicker proximal and thinner distal part, and a parallel orientation at the free epithelial surface. The transition zone between the respiratory epithelium and the MO demonstrates additional developmental features during the first postnatal week. The results are suggestive of incomplete development of MO at birth and ongoing morphological maturation at least up to weaning. We conclude therefore that MO is not vestigial but is functional beyond weaning

Spine density on olfactory granule cell dendrites is reduced in rats reared in a restricted olfactory environment

The Golgi technique was used to study the development of spines on the external dendrites of granule cells in the olfactory bulbs of young rats that had been continuously exposed to cyclohexanone vapor, deodorized air, or rat odors. Exposure to deodorized air for 3 weeks from postnatal day 1 reduced spine density on the medial and lateral sides of the bulb, whilst exposure to cyclohexanone reduced spine density on the lateral side only. These reductions were evident in other animals exposed for 7 weeks. With all treatments, spine density reached a maximum at postnatal day 21 and decreased markedly during the next month

SOLID-PHASE SYNTHESIS OF A SOMATOSTATIN AMIDE ANALOG USING ACID LABILE TERT-BUMEOC PROTECTION AND AN ACID LABILE ANCHOR GROUP

The solid phase synthesis of an amidated somatostatin analogue based on the principle of differentiated acidolysis is described. The acid labile and smoothly cleavable t-Bumeoc moiety (1% TFA/DCM) is used for temporary N(alpha)-protection of D- and L-amino acids and [4-[[[9H-fluoren-9-yl-methoxycarbonyl]amino](4-methoxyphenyl)met hyl]-2-methylphenoxy]acetic acid, attached to an aminomethylated polystyrene resin is used as acid sensitive linker of the solid carrier which releases the peptide in its amide form by treatment with TFA. Its preparation is described in detail