Himasthla quissetensis: uptake and utilization of glucose by rediae as determined by autoradiography and respirometry

Daughter rediae of Himasthla quissetensis removed from the digestive gland of Nassarius obsoletus were placed in sterilized seawater fortified with antibiotics. When [³H]-glucose was added to this medium and autoradiographs were made after 3, 9, and 24 hr of exposure, labeling was observed associated with the redial walls and developing germ balls and cercariae within the brood chambers. Respirometric determinations on starved rediae suspended in the seawater medium with and without glucose revealed the rate of oxygen utilization by rediae exposed to exogenous glucose is significantly elevated. These results are interpreted to mean that the daughter rediae of H. quissetensis can take up and utilize glucose.     

Effect of chain length and concentration of anionic surfactants on the conformational transitions of poly(L-ornithine) and poly(L-lysine) in aqueous solution

The conformation of poly(L-ornithine) (PLO) and poly(L-lysine) (PLL) in solutions of sodium alkyl sulfates, CH₃(CH₂)_nSO₄Na with n = 7, 9, 11, 13 and 15 was studied by circular dichroism. PLO adopts a helical conformation in all 5 homologs and PLL a β-form in only 4 of the homologs. With octyl sulfate PLL has a helical conformation instead. These conformations were observed in solution of surfactants both below and above the critical micelle concentration.     

Gas-liquid chromatographic analysis of cyasin in cycad flour

A method for the quantitative determination of cycasin from cycad flour by gas-liquid chromatography is described. The flour is extracted with 70% ethanol and the residue from the dried extract is directly trimethylsilylated. Androsterone was found to be an excellent internal standard. The average content of cycasin from ten separate analyses of one lot of flour was $\text{0.429 gm}\text{100 gm}$. The method is rapid, sensitive, and not hindered by contaminating compounds.     

Combined in-beam electron impact-B/E-linked scan mass spectrometry of oxazoline derivatives for the structure determination of long-chain unsaturated fatty acids

Long-chain unsaturated fatty acids (UFA) having up to six double bonds are derivatized to 2-substituted 4,4-dimethyloxazolines (DMOX) and then analyzed by combined in-beam electron impact (IBEI)-B/E-linked scan mass spectrometry. This technique provides highly characteristic mass spectra and may serve as an auxiliary means for direct structure determination of individual UFA in mixtures.     

The Epstein-Barr virus (EBV) BZLF1 immediate-early gene product differentially affects latent versus productive EBV promoters.

The Epstein-Barr virus (EBV) BZLF1 gene product is thought to mediate the disruption of latent EBV infection. We have examined the regulatory effects of BZLF1 by studying its transactivating effects on seven different EBV promoters. We find that whereas the BZLF1 gene product increases the activity of the two early promoters, BMLF1 and BMRF1, it decreases the activity of three latent promoters (the BamHI-C and BamHI-W Epstein-Barr nuclear antigen promoters and the latent membrane protein promoter). The BZLF1-induced changes in promoter-directed chloramphenicol acetyltransferase activity occur in EBV-negative as well as EBV-positive cell lines and are accompanied by a similar change in chloramphenicol acetyltransferase mRNA. Deletion analysis of the BamHI Z fragment indicates that in a portion of the amino-terminal half of the BZLF1 gene product (amino acids 24 to 86) is not essential for positive transactivating effects but is required for down-regulating effects. Thus, different domains of the same EBV immediate-early gene product can either increase the function of EBV promoters active in productive infection or decrease the function of key promoters active in latent infection.     

Deletion of C-terminal 12 amino acids of GLUT1 protein does not abolish the transport activity.

We engineered the GLUT1 cDNA to delete C-terminal 12 amino acids of encoded GLUT1 protein. This mutated GLUT1 protein expressed in CHO cells by transfection of its cDNA was demonstrated to reside on the plasma membrane by cell surface labeling technique, and retain the transport activity, similar to that of the wild-type GLUT1. In addition, metabolic labeling of the intact cells with 35S indicated that the half-life of the mutated GLUT1 was not significantly different from that of the wild-type GLUT1. These results suggest that C-terminal 12 amino acids of GLUT1 are not important for the transport activity and the stability of the protein. Taken together with our previous results on the mutant without C-terminal 37 amino acids, the amino acids between the 37th and the 13th from the C-terminus appear to be essential for the transport activity.