Macroevolutionary patterns of male reproductive investment in a clade of parasitic hermaphrodites.

The Eucestoda is particularly relevant for questions concerning reproductive investment in male gametes because no other parasitic group displays such diversity in testis size and number within and among species. This diversity has long been used as a valuable taxonomic character, but few researchers have ever investigated its evolutionary significance. In this paper we investigate the evolution of testis number and size within Rhinebothroides (Platyhelminthes: Eucestoda). Our comparative, phylogenetic analysis revealed that overall allocation to male functions, as measured by relative testicular area, does not change within the clade, even though the packaging of that investment in numerous testes is highly variable within, and diverse among, members of the group.     

The immunogold staining technique for the measurement of lymphocyte subpopulations in bronchoalveolar lavage fluid

The immunogold staining technique was evaluated for use in the identification of lymphocyte subsets in bronchoalveolar lavage fluid. The results obtained compared favorably to the identification of lymphocytes by the E-rosette method, the acid alpha-naphthyl-acetate esterase (ANAE) stain and immunofluorescence microscopy. The main advantages of the immunogold staining method include improved cellular detail and the attainment of permanent preparations, allowing for reassessment, intralaboratory comparison and the performance of further histochemical techniques if desired.     

The diadenosine hexaphosphate hydrolases from Schizosaccharomyces pombe and Saccharomyces cerevisiae are homologues of the human diphosphoinositol polyphosphate phosphohydrolase. Overlapping substrate specificities in a MutT-type protein.

Aps1 from Schizosaccharomyces pombe (Ingram, S. W., Stratemann, S. A. , and Barnes, L. D. (1999) Biochemistry 38, 3649-3655) and YOR163w from Saccharomyces cerevisiae (Cartwright, J. L., and McLennan, A. G. (1999) J. Biol. Chem. 274, 8604-8610) have both previously been characterized as MutT family hydrolases with high specificity for diadenosine hexa- and pentaphosphates (Ap(6)A and Ap(5)A). Using purified recombinant preparations of these enzymes, we have now discovered that they have an important additional function, namely, the efficient hydrolysis of diphosphorylated inositol polyphosphates. This overlapping specificity of an enzyme for two completely different classes of substrate is not only of enzymological significance, but in addition, this finding provides important new information pertinent to the structure, function, and evolution of the MutT motif. Moreover, we report that the human protein previously characterized as a diphosphorylated inositol phosphate phosphohydrolase represents the first example, in any animal, of an enzyme that degrades Ap(6)A and Ap(5)A, in preference to other diadenosine polyphosphates. The emergence of Ap(6)A and Ap(5)A as extracellular effectors and intracellular ion-channel ligands points not only to diphosphorylated inositol phosphate phosphohydrolase as a candidate for regulating signaling by diadenosine polyphosphates, but also suggests that diphosphorylated inositol phosphates may competitively inhibit this process.     

Two-Dimensional NMR Study of Bleomycin and Its Zinc(II) Complex: Reassignment of 13C Resonances

Abstract

Two-dimensional NMR experiments-one bond ¹H- ¹³C correlation spectroscopy and hetero- nuclear multiple bond correlation spectroscopy, both performed in the reverse detection mode-have been employed to unambiguously assign all of the ¹³C resonances of the antibiotic bleomycin and its zinc(II) complex. Previous ¹H resonance assignments of bleomycin (Chen et al. (1977) Biochemistry 16, 2731–2738) were confirmed on the basis of homonuclear Hartmann-Hahn and homonuclear COSY experiments. The ¹³C assignments differ substantially from those previously obtained by other investigators (Naganawa et al., (1977) J. Antibiot. 30, 388–396; Dabrowiak et al., (1978) Biochemistry 17, 4090–4096) but are in agreement with those reported by Akkerman et al.(1988) (Magn. Reson. Chem. 26, 793–802). The more recent study employed similar two-dimensional correlation experiments (performed in the direct detection mode) in conjunction with attached proton tests. Their study often required model compound data to identify carbonyls adjacent to aliphatic moieties. Previous ¹³C NMR studies of the structure, pH titration, and molecular dynamics of bleomycin and its zinc complex have been reinterpreted in terms of the revised assignments.