[Oligonucleotide directed in vitro mutagenesis]

In this study, a method for oligonucleotide directed in vitro mutagenesis was described. It includes the following steps: clone of the gene to be mutated into the phagemid pGCI; preparation of single strand template; design and synthesis of mutated oligonucleotides; synthesis of double strand DNA. Using this method, a new BamHI site was originated at the N terminal of Stx-B and BglII site at the C terminal of Stx-B. It is ready to fuse the Stx-B gene to LamB. This method is a very useful tool for genetic engineering.

Relation between plasma atrial natriuretic peptide (ANP) and glomerular ANP receptors in 5/6 nephrectomized rats

Chronic renal failure (CRF) was induced in male wistar rats (Group I) by 5/6 nephrectomy and the sham-operated ones served as control (Group II). The results showed that in Group I, plasma atrial natriuretic peptide (ANP) levels increased progressively as the Scr was elevated. Plasma R-A rose simultaneously compared to the normal (P less than 0.001). At the 20th week after operation, urine volume and Na decreased significantly (P less than 0.05). The number of glomerular receptors decreased markedly at the 12th week (P less than 0.05) and 20th week (P less than 0.01). Our data suggest that in 5/6 nephrectomized rats, the elevation of plasma ANP level might be partly caused by the damage of glomerular ANP receptors, and the elevated plasma ANP could not play its role in diuresis, natriuresis, blood pressure depression and R-A inhibition as a result of the damage of kidney ANP receptors.