Sex-specific splicing of Z- and W-borne nr5a1 alleles suggests sex determination is controlled by chromosome conformation.

Pogona vitticeps has female heterogamety (ZZ/ZW), but the master sex-determining gene is unknown, as it is for all reptiles. We show that nr5a1 (Nuclear Receptor Subfamily 5 Group A Member 1), a gene that is essential in mammalian sex determination, has alleles on the Z and W chromosomes (Z-nr5a1 and W-nr5a1), which are both expressed and can recombine. Three transcript isoforms of Z-nr5a1 were detected in gonads of adult ZZ males, two of which encode a functional protein. However, ZW females produced 16 isoforms, most of which contained premature stop codons. The array of transcripts produced by the W-borne allele (W-nr5a1) is likely to produce truncated polypeptides that contain a structurally normal DNA-binding domain and could act as a competitive inhibitor to the full-length intact protein. We hypothesize that an altered configuration of the W chromosome affects the conformation of the primary transcript generating inhibitory W-borne isoforms that suppress testis determination. Under this hypothesis, the genetic sex determination (GSD) system of P. vitticeps is a W-borne dominant female-determining gene that may be controlled epigenetically.

Enantioselective separation of racemates using CHIRALPAK IG amylose-based chiral stationary phase under normal standard, non-standard and reversed phase high performance liquid chromatography.

We have previously reported on the solvent versatility of immobilized amylose and cellulose-based chiral stationary phases in enantioselective liquid chromatographic separation of racemates. The studies were mainly focusing on the tris substituted 3,5-dimethylphenylcarbamate polysaccharide-based chiral stationary phases namely CHIRALPAK IA® [Amylose tris (3,5-dimethylphenylcarbamate)] or ADMPC and CHIRALPAK IB® [Cellulose tris (3,5-dimethylphenylcarbamate)] or CDMPC. Here we focus on the application of the recently introduced amylose tris (3-chloro-5-methylphenylcarbamate) or ACMPC and brand name CHIRALPAK IG® with a chlorine substituent replacing the methyl group in CHIRALPAK IA®. This was investigated for the enantioslective separation of different classes of pharmaceuticals namely ß- and α-blockers, anti-inflammatory and antifungal drugs, norepinephrine-dopamine reuptake inhibitor, catecholamines, sedative hypnotics, anti-histaminics, anticancer drugs, antiarrhythmic drugs, flavonoids, amino acids, alpha-2 adrenergic agonist, adrenaline and miscellaneous.A brief comparison between CHIRALPAK IG® and CHIRALPAK IA® under normal standard, non-standard and reversed mobile phase is demonstrated. The results revealed the versatility of the CHIRALPAK IG® column, its compatibility with a wide ranges of solvent and operation modes and its ability to separate chiral compounds not separated with other amylose based chiral stationary phases.