Bicyclo[3.2.1]-DNA: A DNA Analog Containing a Rigid Backbone and a Flexible Base-Pairing Region

Abstract

Bicyclo-[3.2.1]-pyrimidine nucleoside phosphoramidites were synthesized from a common bicyclo-[3.2.1] “sugar” intermediate. Oligomers up to 20 nucleotides in length were synthesized successfully. UV melting curve and thermodynamic analysis of these oligomers reveal stable, antiparallel duplexes     

Estimation of immunoreactive testicular androgen metabolites in the urine of saddle-back tamarins

Hydrolysis, extraction, and radioimmunoassay techniques for the estimation of excreted testosterone metabolites in the urine of saddle-back tamarins have been validated and are described. The steroids measured with the testosterone antiserum used are mostly present as glucuronides and sulfates. Immunoreactivity in high-performance liquid chromatography (HPLC) fractions of urinary extracts and in a standard mixture of cortisol, testosterone, and dihydrotestosterone (DHT) were compared. The fractions with the same retention data as testosterone accounted for the major part of the immunoreactivity. Several other immunoreactive compounds of unknown identity were present in low concentrations. These results suggest that testosterone conjugates are the major steroid metabolites measured with this method in Saguinus fuscicollis. Urinary testosterone levels of castrated males were much lower than those of intact males. Testosterone treatment of castrated males resulted in a temporary superphysiological increase in the levels of urinary testosterone and in an individually variable increase in the levels of the minor immunoreactive compounds. These results suggest that estimation of testosterone metabolite levels in urine is a valid method for the assessment of testicular activity in Saguinus fuscicollis.     

Proteins: biologically relevant components of the scent marks of a primate (Saguinus fuscicollis)

We report here the first documentation that proteins contributeto the scent communication system in a primate. Data presentedhere indicate that high molecular weight compounds which arenot airborne are required for perception of the full attractivenessof the scent. Scent marks from the saddle-back tamarin, a SouthAmerican primate, contain a number of water-soluble proteins.Gel electrophoresis documents that the major protein (66 kD)is found in urine, and a second protein (18 kD) comes from thegland secretions. The 18 kD protein produces two distinct bands(14 kD and 4 kD) under reducing conditions. Concurrent behavioralstudies demonstrate that removal of proteins by enzymatic degradationdoes not alter the ability of the tamarins to discriminate betweenscents from different donor types. However, subtle changes insensory quality occur when the proteins have been degraded.In particular, tamarins do discriminate material in which theproteins have been digested from material in which the proteinsare intact. This observation suggests that proteins are a componentof what constitutes the scent image. In addition, they may serveas carriers and/or reservoirs for more volatile ligands thatencode some of the communicatory messages contained in the material.