Chromosomal localization of seven members of the murine TGF-beta superfamily suggests close linkage to several morphogenetic mutant loci

Chromosomal locations have been assigned to seven members of the TGF-beta superfamily using an interspecific mouse backcross. Probes for the Tgfb-1, -2, and -3, Bmp-2a and -3, and Vgr-1 genes recognized only single loci, whereas the Bmp-2b probe recognized two independently segregating loci (designated Bmp-2b1 and Bmp-2b2). The results show that the seven members of the TGF-beta superfamily map to eight different chromosomes, indicating that the TGF-beta family has become widely dispersed during evolution. Five of the eight loci (Tgfb-1, Bmp-2a, Bmp-2b1, Bmp-2b2, Vgr-1) mapped near mutant loci associated with connective tissue and skeletal disorders, raising the possibility that at least some of these mutations result from defects in TGF-beta-related genes.     

Long-chain alcohol and aldehyde dehydrogenase activities in Acinetobacter calcoaceticus strain HO1-N.

Three alcohol dehydrogenases have been identified in Acinetobacter calcoaceticus sp. strain HO1-N: an NAD(+)-dependent enzyme and two NADP(+)-dependent enzymes. One of the NADP(+)-dependent alcohol dehydrogenases was partially purified and was specific for long-chain substrates. With tetradecanol as substrate an apparent Km value of 5.2 microM was calculated. This enzyme has a pI of 4.5 and a molecular mass of 144 kDa. All three alcohol dehydrogenases were constitutively expressed. Three aldehyde dehydrogenases were also identified: an NAD(+)-dependent enzyme, an NADP(+)-dependent enzyme and one which was nucleotide independent. The NAD(+)-dependent enzyme represented only 2% of the total activity and was not studied further. The NADP(+)-dependent enzyme was strongly induced by growth of cells on alkanes and was associated with hydrocarbon vesicles. With tetradecanal as substrate an apparent Km value of 0.2 microM was calculated. The nucleotide-independent aldehyde dehydrogenase could use either Würster's Blue or phenazine methosulphate (PMS) as an artificial electron acceptor. This enzyme represents approximately 80% of the total long-chain aldehyde oxidizing activity within the cell when the enzymes were induced by growing the cells on hexadecane. It is particulate but can be solubilized using Triton X-100. The enzyme has an apparent Km of 0.36 mM for decanal.     

Somatostatin and lanthanum discriminate two Ca2+ mobilizing mechanisms regulated by bombesin receptors in peptic cells

Bombesin (BB)-stimulated pepsinogen secretion from frog esophageal peptic acini was inhibited 40% by somatostatin (SS) (IC50 = 1 nM), and by 30-50% by low concentrations (10(-7)-10(-4)M) of lanthanum chloride. SS inhibited basal secretion as well as both early (0-2 min) and late (2-30 min) BB-stimulated secretory phases. By contrast, LaCl3 selectively inhibited the late secretory phase and was without effect on basal secretion. SS (100 nM) and LaCl3 (30 microM) attenuated BB-stimulated 45Ca2+ uptake, and the combination resulted in additive inhibition. High K+ media decreased basal secretion, abolished SS but not LaCl3 inhibition of BB-stimulated secretion, and blocked SS inhibition of BB-mediated 45Ca2+ uptake. These findings suggest the existence on peptic cells of distinct La3+-sensitive, and somatostatin-sensitive, K+ dependent, Ca2+ mobilizing mechanisms which contribute to BB receptor-mediated secretion.     

Taxonomy of agamic complexes in plants: A role for metapopulation thinking

The argument is made that species should be comparable with respect to the numbers of genotypes they include, regardless of whether their reproduction is exclusively sexual or not. Specifically, this means recognizing species at a level comparable to that of the section or series, as these are used in genera likeCrataegus L. orTaraxacum Weber ex F.H.Wigg. Anticipated advantages of this approach for the taxonomy of agamic complexes include the following: (1) a common basis for communication between taxonomists and population biologists, hence (2) the opportunity to find possible explanations for patterns of variation in theoretical models of population behavior. In addition, (3) revising the hierarchical level at which species are recognized will make it easier to avoid describing species that are paraphyletic, i.e. that include some but not all related genotypes sharing a common ancestor. As an example, revising the hierarchical level at which species are recognized makes it possible to see many agamic complexes as being made up of metapopulations of genotypes that arise and go extinct as habitats become available and then disappear for whatever reason (succession, disturbance, etc.) and at whatever scale (local, regional, continental).     

Synthesis, Biological Properties, and Structure-Activity Relationships of Quinoxaline Angiotensin II Receptor Antagonists

Quinoxaline heterocycle containing angiotensin II receptor antagonist analogs were prepared. All five analogs reported here display potent antagonistic activities and most interestingly, quinozaline bis-N-oxide 10 exhibits very potent activities both in binding and functional assays.     

Combined 13C NMR- and mass-spectrometry for non-invasive monitoring of metabolism

Summary A method for the long-term incubation of cell suspensions at measured dissolved gas concentrations during acquisition of NMR spectra is described: a mass spectrometer probe in the cell suspension provides continuous monitoring of gases. Its usefulness is shown for Trichomonas vaginalis where fermentation products from glucose in 72 M O₂ are different from those under strictly anaerobic conditions.     

A simple method for the direct extraction of plasmid DNA from yeast

Summary A rapid and simple method for the small scale isolation of shuttle plasmid DNA from Saccharomyces cerevisiae is described. It uses glass beads to break cells and reagents which are also used in bacterial mini-preps to yield plasmid DNA without chromosomal contamination in sufficient quantities to enable direct visualisation on agarose gels.     

Induction of division synchrony in Tetrahymena pyriformis by a single hypoxic shock. Its use in elucidating control of the cell cycle by adenosine 3':5'-monophosphate.

A single hypoxic shock was used to induce division synchrony in Tetrahymena pyriformis. Hypoxia results in accumulation of the cells in the G2 phase of the cell cycle. Cyclic AMP and adenyl cyclase activity were measured in this system. Cell-cycle blockade was associated with extraordinarily high levels of intracellular cyclic AMP. After release from hypoxia, the cells retain a characteristic pattern of modulation of cyclic AMP associated with division that is found in selection-synchronized cells. The results are discussed with reference to other methods of induction synchrony and related studies on the natural cell cycle in this organism.     

Isolation of uridine 5'-pyrophosphate glucuronic Acid pyrophosphorylase and its assay using p-pyrophosphate

A procedure was devised to detect and assay uridine 5′-pyrophosphate (UDP)-glucuronic acid pyrophosphorylase in plant extracts. Substrates are UDP-glucuronic acid and ³²P-pyrophosphate, and the ³²P-uridine 5′-triphosphate produced is selectively adsorbed to charcoal. The charcoal adsorption procedure is a modification of that used to determine ³²P-adenosine 5′-triphosphate produced by adenosine 5′-pyrophosphate glucose pyrophosphorylase, and the modification greatly improves the retention of uridine 5′-triphosphate.