2'-Deoxyguanosine (3) and native DNA both give rise to exocyclic 1,N2-(1,3-propano)-2'-deoxyguanosine adducts 6 and 7 upon treatment with acrolein (1), a known mutagen, in vitro under physiological conditions. The use of synthetic deoxyoligonucleotides containing adduct 6 or 7 could shed light on the mechanism of the mutagenicity of 1 and on the nature of the structural perturbations present in DNA duplexes where they are present. Unfortunately, this is precluded by the instability of 6 and 7 to the conditions of automated DNA synthesis. We have prepared 1,N2-(1,3-propano)-2'-deoxyguanosine (PdG) (8) as a stable model for 6/7. The structure of 8 has been verified by magnetic resonance, ultraviolet spectroscopy, and mass spectrometry. This moiety has been incorporated into oligodeoxynucleotides via solid-state synthesis technology. Negative ion fast atom bombardment (FAB) mass spectrometry of the pentaoligodeoxynucleotide 5'-GT(PdG)CG-3' verified the identity and position of the modified base. The validity of 8 as a model system for the adduct pair 6/7 in structural and biological studies of DNA duplexes is discussed.

Acrolein↗

PubMedDate not supplied

Sympathetic nerve activity and blood pressure in normotensive backcross rats genetically related to the spontaneously hypertensive rat.

The genetic basis of hyperactivity of the sympathetic nervous system (SNA) in spontaneously hypertensive rats (SHR) was assessed by measuring SNA in animals derived from a backcross (BC) breeding program designed to isolate single gene differences causing changes in blood pressure. Selective breeding of the male hypertensive rats with inbred normotensive female Wistar/Lewis rats yielded progeny with a range of blood pressures, but whose group mean pressures were lower than the group mean pressures of the original SHR. Progressive generations had progressively lower group mean pressures. There was a positive correlation between SNA and mean arterial pressure in BC rats. These results indicate that the genetic defect in SHR may be abnormality in SNA, and the hypertension in these animals is a secondary result of this primary defect. Baroreceptor function was also assessed in SHR and in BC rats. In young (8 to 24 weeks old) SHR, baroreceptor function was similar to that in BC rats, whereas SNA was markedly increased. Only in older (24 to 40 weeks old) SHR was there an abnormality in the gain of baroreceptors. The development of hypertension in SHR therefore appears to be due to increased SNA resulting from a defect in the central nervous system. Changes in baroreceptor function are secondary to the hypertension and occur after the hypertension is established.

Aging↗

PubMedDate not supplied

Changes in the enzyme levels of mouse organs after leukemogenic doses of x-ray and treatment with radiation leukemia protection factor.

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Alkaline Phosphatase↗

PubMedDate not supplied

Production of chymosin for the dairy industry by recombinant DNA technology.

The increasing world production of cheese, coupled with a decline in the number of slaughtered calves, has stimulated a search for alternative sources of chymosin. This article briefly reviews microbial alternatives to chymosin and discusses chymosins produced using recombinant DNA technology. Recombinant chymosin represents one of the first successful applications of recombinant DNA technology in the food industry.

Base Sequence↗