The effect of carbamylcholine on CFU-s differentiation

The proportion of spleen colony-forming units (CFU-s) killed by hydroxyurea was greatly increased after bone marrow cells (BMCs) from LACA mice were exposed to carbamylcholine (Cach; 1 X 10(-13) to 1 X 10(-9) in vitro and there was a marked change in the proportion of spleen colony types. Following treatment with Cach, granulocytic and mixed erythroid-type colonies increased from 20 to 26.3% and 16.1 to 29.6% in 9-day colonies and from 8.3 to 28.2% and 21.7 to 39.4% in 13-day colonies, respectively. Single cell suspensions of spleen colonies were made for granulocyte-macrophage progenitor (CFU-gm) and late erythroid progenitor (CFU-e) assays. The number of CFU-gm from Cach-treated BMC was about twice that from control BMC for both day 9 and day 13 groups; the number of CFU-e decreased relatively. The results suggest that cholinergic receptors on CFU-s may increase the tendency to differentiate into the granulocytic/monocytic line.     

The macrosatellites of the Toulouse goose: the major tandemly repetitive DNA in the toulouse goose genome

This paper examines the principal classes of repetitive DNA of the Toulouse goose (Anser anser) genome. There are four major classes and they are tandem repeats of less than 200 base pairs (bp). The longest repeat (class A) is 190 bp long and starts with a HinfI site. Class B is 43 bp long, commencing with a FokI site. Classes A and B show no extensive homology to DNA sequences held on a current data base (Genbank) but were confirmed to exist as major repeats in another strain of goose, the Emden goose (Anser anser) genome. Classes C and D are 5-bp repeats of 5' GAGAG 3' and 5' GGGAA 3', respectively. The macrosatellites C and D were compared with a current data base (Genbank) and were found to exist in a variety of other organisms as satellites.     

Viewing molecules with scanning tunneling microscopy and atomic force microscopy

Two new microscopic techniques make it possible to obtain images of biologically interesting molecules directly in air, vacuum, or under water. Scanning tunneling microscopy and atomic force microscopy both have the capacity to visualize atoms on the surface of rigid structures and provide details of molecular structure for lipids, proteins, carbohydrates, and nucleic acids. In addition to providing visualizations of individual molecules, these scanning probe techniques allow direct imaging of complexes between molecules or between molecules and higher-order subcellular structures such as membranes and cytoskeletal components. Both microscopes can be operated under a variety of ambient conditions ranging from high vacuum to above atmospheric pressure. Specimens need not be dry; both techniques have been used to image molecules in aqueous media under nearly physiological conditions. It is proposed that as these techniques mature they will allow direct observation of many molecular interactions under physiological conditions or even in vivo while they are occurring within the cell.     

Waste water treatment using saline cultures of microalgae

Summary Survival of microorganisms (Escherichia coli has been used as an example) is affected by a combination of salinity and high pH induced by the active photosynthesis of marine microalgae (Aphanotece or Dunaliella sp.). This effect can be applied to create a more efficient wastewater treatment process using algal stabilization ponds.     

Insulin-stimulated alpha-(methyl)aminoisobutyric acid uptake in skeletal muscle. Evidence for a short-term activation of uptake independent of Na+ electrochemical gradient and protein synthesis.

1. The present study was designed to explore the mechanisms by which insulin stimulates system A of amino acid transport in extensor digitorum longus (EDL) muscles, by using a system A analogue, alpha-(methyl)aminoisobutyric acid (MeAIB). 2. Insulin stimulation of MeAIB uptake was noted after only 30 min of incubation and was maximal at 60 min. Kinetics of the insulin effect on MeAIB uptake were characterized by an increased Vmax. without modification of Km for MeAIB. 3. Incubation of EDL muscles with cycloheximide for 90 min did not modify MeAIB uptake in either the presence or the absence of insulin, indicating the independence of insulin action from protein synthesis de novo. Incubations for 180 min with cycloheximide caused a decrease in basal MeAIB uptake; however, the percentage stimulation of amino acid transport by insulin was unaltered. Basal MeAIB uptake was increased by incubation for 180 min, but under these conditions no change in the percentage effect of insulin was found. 4. Ouabain, gramicidin D, or both, markedly decreased basal MeAIB uptake by EDL muscle, but the percentage effect of insulin was unaltered. 5. We conclude that insulin action on amino acid transport through system A in muscle is rapid, is characterized by an increased Vmax., and is independent of protein synthesis de novo and the Na+ electrochemical gradient. Our data are compatible with insulin acting directly on the system A transporter.     

Adipose-tissue-specific increase in glyceraldehyde-3-phosphate dehydrogenase activity and mRNA amounts in suckling pre-obese Zucker rats. Effect of weaning.

The regulation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene expression was studied during the onset of obesity in the genetically obese (fa/fa) rat by determination of GAPDH activity and hybridizable mRNA amounts in adipose tissue and liver from suckling and weanling rats. GADPH activity remained low throughout the suckling period, and a burst of activity occurred after weaning in both lean and obese pups. As early as 7 days of age, adipose tissue from pre-obese rats displayed a significant increase in enzyme activity, whereas no difference could be detected in the liver. In both suckling (16 days of age) and weanling (30 days of age) obese rats a proportionate increase in GAPDH activity and mRNA amounts was observed in adipose tissue, but not in liver. It is concluded that the obese genotype influences GAPDH gene expression at a pretranslational level and in a tissue-specific manner. This phenomenon could partly contribute to the hyperactive fat accretion in the obese rat, since glycolysis is the major metabolic pathway for lipogenic substrates in adipose tissue.