A new hereditary single band variant of the Gc system

Summary A new single band variant (Gc Ar) or the Gc subtypes not identical with the known Gc variants has been detected in the plasma of a healthy blood donor by isoelectric focusing. Using this technique the variant is represented by a single band which has a similar isoelectric point to the Gc 1C2 anodal band. It is well known that the single band Gc phenotypes remain unaltered after neuraminidase treatment. Nevertheless, the new single band variant (Gc Ar) is altered after neuraminidase treatment as is Gc 2A3. After neuraminidase treatment, the Gc Ar band is affected and moved to the nearby position of the Gc 2 band. Investigation of the proband's family shows that the variant occurs combined with the common alleles Gc 1F, Gc 1S and that it has an autosomal dominant inheritance.     

Effects of ingested phytoecdysteroids on the growth and development of two Lepidopterous larvae

The effects of ingested or injected 20-hydroxyecdysone on silkworm larvae (Bombyx mori) including death without moulting, death following completion of promoted moulting, death during promoted moulting (ecdysis inhibition) and inhibition in growth with and without effects on moulting, are dependent upon the concentration of exogenous hormone, the precise developmental stage of the treated larvae, and the duration of exposure to the exogenous ecdysteroid. Comparisons of 20-hydroxyecdysone with other phytoecdysteroids in the silkworm and pink bollworm, Pectinophora gossypiella, show a similar but more potent effect induced by ponasterone A, while cyasterone causes an ‘antiecdysone’ effect.     

R-Factor Mutant Capable of Specifying Hypersynthesis of Penicillinase

The physical characteristics of a mutant, R(M201-2), capable of conferring high and stable ampicillion resistance was analyzed. The R(M201-2) and its parent R-factor deoxyribonucleic acid (DNA) could be isolated as an extrachromosomal and covalently closed circular form. Their buoyant densities were both 1.712 g/cm(3), and their molecular weights were about 82 x 10(6) and 64 x 10(6), respectively, when measured by CsCl and sucrose density gradient analyses. The contour lengths by electron microscopy were 35.9 +/- 0.6 and 31.0 +/- 0.6 mum, respectively. By using the extracted R-factor DNA, the mutant and parent characters were transformable to another Escherichia coli strain. The mutant R factor showed an increased amount of DNA even after conjugal transfer to Proteus. An increase in the size of R-factor DNA was thus considered to be the cause of the high level of ampicillin resistance.     

Genetic analysis of streptomycin-resistance and-dependence inChlamydomonas

Summary Three non-chromosomal and two chromosomal genes which influence resistance to streptomycin are described. Each of the non-chromosomal factors,sr-500,sr-1500, andsd, exhibits uniparental inheritance, with all progeny receiving the factor when it is carried by the parent of mating-typeplus, and none when it is carried by the mating-typeminus parent. The streptomycin-dependence factor,sd, shows zygotic dominance when contributed by the mating-typeplus parent, but not when coming from the mating-typeminus parent, indicating that the uniparental transmission results from events occurring within the zygote early in maturation and well before meiosis. The chromosomal geneA interacts both with chromosomal and non-chromosomal genes at the biochemical level, but does not alter their patterns of inheritance.With 1 Figure in the TextThis paper is dedicated to ProfessorL. C. Dunn in gratitude to him as teacher and advisor, on the occasion of his retirement.This work was supported by grants from the U.S. Public Health Service and the National Science Foundation. The generosity and interest of ProfessorFrancis J. Ryan in providing laboratory space is gratefully acknowledged, as is the technical assistance of MissFran Yablonsky.     

High-performance liquid chromatographic separation of bile acid pyrenacyl esters with cyclodextrin-containing mobile phase

The high-performance liquid chromatographic separation of bile acid pyrenacyl esters with cyclodextrin-containing mobile phase is presented. Compared with conventional methods, inclusion chromatography gives much more satisfactory separation of derivatized bile acids in a short time. The application of this method to the separation of glycine-conjugated bile acids in human bile is also described.     

Immunocytochemical localization of GABA containing neurons in the ventrolateral medulla oblongata of the rat

Summary Localization of -aminobutyric acid (GABA) in the ventrolateral medulla oblongata of the rat was studied, using antisera directed against GABA molecule fixed to bovine serum albumin. Within the rostral portion of the ventrolateral medulla, GABA-like immunoreactive neurons were found in the lateral wing of the raphe magnus and in the region of the paragigantocellular reticular nucleus. In the caudal portion of the ventrolateral medulla, a lesser number of GABA-stained neurons were found in the region around the nucleus reticularis lateralis. GABA-like immunoreactive punctate structures were also found throughout the ventrolateral medulla. These results provide further evidence for the existence of GABAergic neurons in the ventrolateral medulla oblongata of the rat.     

A New Enzymatic Cycling Technique for Glutamate Determination in Brain Microdialysates

A quantitative analysis of glutamate in brain dialysate was made by using an enzymatic cycling technique. This method made it possible to measure the concentration of glutamate in dialysate collected at 30-s intervals. Dialysates were collected from Mongolian gerbil hippocampus before, during, and after two 90-s ischemic insults at an interval of 5 min. An extracellular increase in levels of glutamate was already observed in samples collected during a 30-60 s period after the onset of each ischemia, and the levels of glutamate were maximal at the end of each period of ischemia (approximately a fourfold increase). The increased levels of glutamate rapidly returned almost to preischemic levels by 30 s of recirculation. This method will provide more precise information about temporal changes in the extracellular glutamate concentration in the brain during ischemia.     

Alpha beta T cell receptor and CD3 transduce different signals in immature T cells. Implications for selection and tolerance

Ligand binding to alpha beta TCR has different consequences in thymocytes at different developmental stages, causing alternatively positive selection, clonal deletion, or activation. These various functional consequences may be due to changes in the signaling properties of the receptor complex during development. In this report we show that alpha beta TCR engagement on immature thymocytes has different effects on intracellular free calcium concentrations than alpha beta TCR engagement on mature T cells. In contrast, CD3 engagement on immature thymocytes and mature T cells has the same effect on intracellular free calcium, suggesting that altered signal transduction in immature thymocytes may be due to inefficient alpha beta TCR-CD3 coupling. These studies also suggest that in certain T cell populations, activation events resulting from ligation of CD3 may not accurately reflect the activation events resulting from ligation of the physiologic receptor, alpha beta TCR.