The stoichiometry of peptide-heparan sulfate binding as a determinant of uptake efficiency of cell-penetrating peptides

Binding to negatively charged heparan sulfates (HS) at the cell surface is considered the first step in the internalization of cationic cell-penetrating peptides (CPPs). However, little is known about the relation of the characteristics of the HS-CPP interaction such as affinity, stoichiometry, and clustering with uptake. In this study, we investigated a collection of mutants of a cyclic CPP derived from human lactoferrin with respect to HS binding and uptake. The thermodynamic parameters of HS binding were determined by isothermal titration calorimetry, clustering of HS was investigated by dynamic light scattering, and cellular uptake by flow cytometry and confocal microscopy. Whereas mutations of non-arginine amino acids that are conserved across lactoferrins of different mammalia only had a minor effect on uptake efficiency, changes in the number of arginine residues influenced the uptake significantly. In general, introduction of arginine residues and cyclization improved the HS affinity and the ability to cluster HS. In particular, there was a strong negative correlation between stoichiometry and uptake, indicating that crosslinking of HS is the driving force for the uptake of arginine-rich CPPs. Using glycan microarrays presenting a collection of synthetic HS, we show that a minimal chain length of HS is required for peptide binding.     

Cholesterol 7alpha-hydroxylase activity of the rat liver after hypophysectomy and administration of hypophyseal hormones (author's transl)]

In order to elucidate the role of the hypophysis in the regulation of cholesterol 7alpha-hydroxylase activity, male and female rats hypophysectomized on day 50 of life were treated with different hypophyseal hormones and tested on day 85 of life. Only a crude extract from human hypophysis and ovine prolactin was able to enhance the enzyme activity, thereby restoring the level of intact controls.     

Sexual steroids and monamine metabolism during gestation.

The experiments show influence of progesterone and estradiol on regulation of enzymes of monamine metabolism, MAO and COMP during pregnancy. Both the hormones inhibit enzymes MAO and COMPT in the adrenals when determined at 0 h parturition. Estradiol has stronger inhibitory effect than progesterone. The results provide evidence for important endocrine implication during pregnancy for processes of monamine regulation.     

Neurosecretion and hydroelectrolytic regulation in Artemia salina (author's transl)]

The activity of Artemia protocerebral median neurosecretory cells is stimulated when animals are grown in media whose tonicity is lower than that of sea weater. The substance liberated by these cells could regulate the tonicity of the internal medium.     

Biochemical markers in the taxonomy of the Actinomycetales.

Useful biochemical markers for the classification of Actinomycetales are: 1. DL- or LL-diaminopimelic acid in the peptidoglycan, 2. sugar composition of polysaccharides, 3. fatty acid spectrum of cell lipids. The occurrence of various kinds of branched fatty acids and of unsaturated fatty acids is of special value.     

Age and peritoneal fluid cellular distribution in women 20-40 years of age.

Cytologic aspiration specimens of peritoneal fluid revealed that mesothelial cell proportions were significantly reduced 19.2% in women between 26 and 35 years of age. Possibly, mesothelial cell renewal was decreased in women of the older age groups.