AIDS in Africa: distinguishing fact and fiction.

The data widely purporting to show the existence and heterosexual transmission in Africa of a new syndrome caused by a retrovirus which induces immune deficiency are critically evaluated. It is concluded that both acquired immune deficiency (AID) and the symptoms and diseases which constitute the clinical syndrome (S) are of long standing in Africa, affect both sexes equally and are caused directly and indirectly by factors other than human immunodeficiency virus (HIV). Seropositivity to HIV in Africans usually represents no more than cross-reactivity caused by an abundance of antibodies induced by the numerous infectious and parasitic diseases which are endemic in Africa. The apparently high prevalence of 'AIDS' and 'HIV' seropositives is therefore not surprising and is not proof of heterosexual transmission of either HIV or AIDS.

Metabolism of Monoterpenes : Metabolic Fate of (+)-Camphor in Sage (Salvia officinalis).

The bicyclic monoterpene ketone (+)-camphor undergoes lactonization to 1,2-campholide in mature sage (Salvia officinalis L.) leaves followed by conversion to the beta-d-glucoside-6-O-glucose ester of the corresponding hydroxy acid (1-carboxymethyl-3-hydroxy-2,2,3-trimethyl cyclopentane). Analysis of the disposition of (+)-[G-(3)H]camphor applied to midstem leaves of intact flowering plants allowed the kinetics of synthesis of the bis-glucose derivative and its transport from leaf to root to be determined, and gave strong indication that the transport derivative was subsequently metabolized in the root. Root extracts were shown to possess beta-glucosidase and acyl glucose esterase activities, and studies with (+)-1,2[U-(14)C]campholide as substrate, using excised root segments, revealed that the terpenoid was converted to lipid materials. Localization studies confirmed the radiolabeled lipids to reside in the membranous fractions of root extracts, and analysis of this material indicated the presence of labeled phytosterols and labeled fatty acids (C(14) to C(20)) of acyl lipids. Although it was not possible to detail the metabolic steps between 1,2-campholide and the acyl lipids and phytosterols derived therefrom because of the lack of readily detectable intermediates, it seemed likely that the monoterpene lactone was degraded to acetyl CoA which was reincorporated into root membrane components via standard acyl lipid and isoprenoid biosynthetic pathways. Monoterpene catabolism thus appears to represent a salvage mechanism for recycling mobile carbon from senescing oil glands on the leaves to the roots.

RNase H is not involved in the induction of stable DNA replication in Escherichia coli.

rnh mutations of Escherichia coli inactivating RNase H activity allow the initiation of rounds of DNA replication in the absence of protein synthesis (stable DNA replication). However, levels of RNase H did not change during or after the induction of stable DNA replication in rnh+ strains by incubation with nalidixic acid or UV irradiation.

Purification of monoterpenyl glycosides by gel-permeation and hydrophobic-interaction chromatography on polyacrylamide (Bio-Gel P-2).

Hydrophobic interaction of the aglycone of monoterpenyl glycosides with the polyacrylamide matrix of Bio-Gel P-2 greatly retards the elution of these substances when chromatographed in dilute aqueous sodium chloride. This hydrophobic interaction is eliminated by inclusion of 15% acetonitrile in the eluant, thereby permitting conventional gel-permeation chromatography. Combination of these techniques by sequential chromatography on the same Bio-Gel column, in the hydrophobic interaction mode followed by the gel-permeation mode, provides a simple, yet mild and highly selective procedure for the purification of monoterpenyl glycosides from crude plant extracts. Examination of the chromatographic properties of beta-D-glucopyranosides and beta-D-galactopyranosides of a number of acyclic, monocyclic, and bicyclic monoterpenols indicates that the extent of hydrophobic interaction is of diagnostic value in determining the nature of the aglycone.

Metabolism of monoterpenes: lactonization of (+)-camphor and conversion of the corresponding hydroxy acid to the glucoside-glucose ester in sage (Salvia officinalis).

The bicyclic monoterpene ketone (+)-camphor is a major constituent (up to 26%) of the volatile oil of immature sage (Salvia officinalis L.) leaves; however, as the plant matures the content of this ketone declines in the fully expanded leaves (to about 65% of maximum) as does the overall yield of oil (to roughly 60% of maximum). Examination of the metabolism of (+)-[G-3H]camphor in discs prepared from mature leaves of flowering sage plants revealed that this ketone was converted to a water-soluble metabolite which on chromatographic analysis proved to be considerably more polar than a simple monoterpenyl glycoside. Mass spectral analysis of several derivatives of the terpenoid moiety of the metabolite obtained from large-scale incubations allowed identification of the aglycone, while degradative studies and detailed radiochromatographic analyses indicated that the metabolite contained two glucose residues; one glycosidically linked and the other in ester linkage. All of the evidence was consistent with the initial lactonization of camphor to 1,2-campholide followed by conversion to the beta-D-glucoside-6-O-glucose ester of the corresponding hydroxy acid (1-carboxymethyl-3-hydroxy-2,2,3-trimethyl cyclopentane). Direct evidence for the intermediacy of 1,2-campholide was also obtained through isotopic dilution experiments and by direct testing of the labeled lactone. The lactonization of camphor in sage resembles a similar step in the catabolism of camphor by microorganisms, but appears to be the first report of this reaction type in higher plants.