Designation of Streptomycete 16S and 23S rRNA-based target regions for oligonucleotide probes.

The 16S and 23S rRNA of various Streptomyces species were partially sequenced and screened for the presence of stretches that could define all members of the genus, groups of species, or individual species. Nucleotide 929 (Streptomyces ambofaciens nomenclature [J.L. Pernodet, M.T. Alegre, F. Boccard, and M. Guerineau, Gene 79:33-46, 1989]) is a nucleotide highly unique to Streptomyces species which, in combination with flanking regions, allowed the designation of a genus-specific probe. Regions 158 through 203 of the 16S rRNA and 1518 through 1645 of the 23S rRNA (helix 54 [Pernodet et al., Gene 79:33-46, 1989]) have a high potential to define species, whereas the degree of variation in regions 982 through 998 and 1102 through 1122 of the 16S rRNA is less pronounced but characteristic for at least certain species. Alone or in combination with each other, these regions may serve as target sites for synthetic oligonucleotide probes and primers to be used in the determination of pure cultures and in the characterization of community structures. The specificity of several probes is demonstrated by dot blot hybridization.     

Chronopharmacokinetics and Cardiovascular Effects of Nifedipine

Orcadian phase dependency in pharmacokinetics and hemodynamic effects on blood pressure and heart rate of different galenic formulations of nifedipine (immediate-release, sustained-release, and i.v. solution) were studied in healthy subjects or in hypertensive patients. Pharmacokinetics of immediate-release but not sustained-release and i.v. nifedipine were dependent on time of day: immediate-release nifedipine had higher C_max (peak concentration) and shorter t_max (time-to-peak concentration) after morning than evening application, and bioavailibility in the evening was reduced by about 40%. Orcadian rhythm in estimated hepatic blood flow as determined by indocyanine green kinetics may contribute to these chronokinetics. A circadian time dependency was also found in nifedipine-induced effects on blood pressure and heart rate as monitored by 24-h ambulatory blood pressure measurements. In conclusion, the dose response relationship of oral nifedipine is influenced by the circadian organization of the cardiovascular system as well as by the galenic drug formulation.     

Characterization and regional mapping of new anonymous chromosome 20-specific DNA markers isolated from a flow-sorted DNA library

Employing the flow-sorted chromosome 20-specific DNA library LL20NS01, we isolated seven novel unique poly- and monomorphic DNA markers specific to human chromosome 20. Initially, 201 phage clones were analyzed regarding insert size and repetitivity. By testing 14 single- and low-copy number clones for their ability to detect RFLPs, three polymorphisms were revealed by two probes, pFMS22-1.4 [D20S22] and pFMS76 [D20S23]. Seven of twenty probes (35%) were assigned to chromosome 20 using a somatic cell hybrid DNA panel. Five of them were regionally mapped by in situ hybridization. Three DNA markers, pFMS51 [D20S29], pFMS76 [D20S23], and pFMS106 [D20S30], were assigned to 20p11.2-p12, and two markers, pFMS22-1.4 [D20S22] and pFMS135 [D20S31], to 20q12-q13.3. Our new chromosome 20-specific DNA markers should be useful for the molecular characterization of this rather underpopulated human chromosome.     

Identification of Strychnine Binding Sites in the Rat Retina

Abstract: [³H]Strychnine specifically binds to membrane fractions isolated from rat retinae. The binding is saturable, with an apparent dissociation constant, K _D, of 14.3 × 10⁻⁹ M and 205 fmol bound/mg protein. Specific binding is time-dependent and proportional to protein concentration. Glycine and taurine are equally potent inhibitors of [³H]strychnine binding ( K _i= 4 × 10⁻⁵ M); no other amino acids endogenously present in the retina inhibited [³H]strychnine binding.     

Nucleoside uptake by rat retina cells

Adenosine and guanosine uptake have been studied in the rat retina. Both nucleosides are taken up in a time- and temperature-dependent manner by dispersed rat retinal cells. The uptake of both nucleosides is Na⁺-dependent and Ca⁺⁺-independent. Initial rate studies of guanosine and adenosine uptake demonstrate a single uptake process for each nucleoside with K_D values of 2.1 and 2.9 uM, and maximal rates of 24 and 17 pmol/mg protein/min, respectively. Guanosine uptake was inhibited by adenosine with a K_I of 12.1 uM whereas guanosine inhibited adenosine uptake with a K_I value greater than 10^?3 M. LN⁶-phenylisopropyladenosine, a nucleoside analog, was the most potent inhibitor of adenosine and guanosine uptake with K_I values of 25 and 8 uM, respectively. Phosphodiesterase inhibitors (isobutylmethylxanthine and theophylline) and biogenic amines (dopamine, norepinephrine, and histamine) had no significant effect on the uptake of guanosine or adenosine at concentrations up to 100 uM.     

Primary structure of yeast proteinase B inhibitor 2.

The complete amino acid sequence of yeast proteinase B inhibitor 2 (IB2) was determined to be H3N+-Thr-Lys-Asn-Phe-Ile-Val-Thr-Leu-Lys-Lys-Asn-Thr-Pro-Asp-Val-Glu-Ala-Lys-Lys-Phe-Leu-Asp-Ser-Val-His-His-Ala-Gly-Gly-Ser-Ile-Leu-His-Glu-Phe-Asp-Ile-Ile-Lys-Gly-Tyr-Thr-Ile-Lys-Val-Pro-Asp-Val-Leu-His-Leu-Asn-Lys-Leu-Lys-Glu-Lys-His-Asn-Asp-Val-Ile-Glu-Asn-Val-Glu-Asp-Lys-Glu-Val-His-Thr-Asn-COO-. Elucidation of the primary structure was enabled by automated Edman degradation and COOH-terminal hydrolysis with carboxypeptidases A (bovine pancreas and Y (yeast). IB2 is the first proteinase inhibitor to be sequenced that possesses a structure devoid of disulfide bridges.     

Aspects of the cross transmission to Galleria mellonella of a Baculovirus from the alfalfa looper, Autographa californica

The nuclear polyhedrosis virus originally isolated from the alfalfa looper, Autographa californica, was successfully transmitted to the greater wax moth, Galleria mellonella. Both the many polyhedra per nucleus (MP) and the few polyhedra per nucleus (FP) plaque variants of this virus were found to be infective when injected intracoelomically. When polyhedra of each plaque variant were fed to G. mellonella larvae, a difference in response was observed; the MP plaque variant was estimated to be 30 times more infective than the FP variant.