Ethanol utilization regulatory protein: profile alignments give no evidence of origin through aldehyde and alcohol dehydrogenase gene fusion.

The suggestion that the ethanol regulatory protein from Aspergillus has its evolutionary origin in a gene fusion between aldehyde and alcohol dehydrogenase genes (Hawkins AR, Lamb HK, Radford A, Moore JD, 1994, Gene 146:145-158) has been tested by profile analysis with aldehyde and alcohol dehydrogenase family profiles. We show that the degree and kind of similarity observed between these profiles and the ethanol regulatory protein sequence is that expected from random sequences of the same composition. This level of similarity fails to support the suggested gene fusion.     

Contribution to the structural characterization of eucaryotic PSI reaction centre—I. Critical analysis of the polypeptidic composition of different P700 enriched fractions

In thylakoid membranes, several peptides of high MW are present which may interfere with the study of CP1's components. Modifying Cleveland's technique [7] for limited proteolysis, we have characterized the polypeptides found in the 60 kD region. Some may result from incomplete washing of the CF1 while others come from the CP1; indeed, this chlorophyll protein complex, which has a higher MW (above 100 kD), very often undergoes a dissociation into smaller components of about 60 KD MW.Analysis of the protein content of different preparations commonly used to obtain PSI reaction centre enriched fractions has been performed. The and subunits of CF1 are among the main contaminants of most of these preparations. A further purification step is described which can be applied to all these preparations, but numerous peptides are still present in the active fractions. It is most unlikely that all these polypeptides are required for the primary photochemical event, and this emphasizes the necessity to find a new simple method to purify PSI reaction centres.     

Histochemistry of the juxtaglomerular apparatus in the toad Bufo bufo

Summary An investigation regarding the question of whether there exists a macula densa as part of the juxtaglomerular apparatus in the kidney of amphibians has been carried out. With the aid of a histochemical reaction for glucose-6-phosphate dehydrogenase activity, the presence of a macula densa zone as a specialized part of the distal tubule in the toad Bufo bufo was demonstrated. The functional significance of the high glucose-6-phosphate dehydrogenase activity in the macula densa cells is discussed.     

The mitochondrial complex in cryptophyceae

The unitary nature of the mitochondrion and the characteristic flattened finger-like morphology of the cristae were demonstrated in the Cryptophyceae. Hemiselmis rufescens contained an unbranched vermi-form mitochondrion in contrast to the variously branched complex, comprising an interconnected peripheral and central reticulum, in Chroomonas sp. and strains of Cryptomonas. The systematic value of the shape and distribution of the mitochondria in the examined genera was suggested.     

Rat and human embryo and post-natal sera contain a potent endogenous competitor of estrogen-rat alpha-fetoprotein interactions

A highly active inhibitor of the binding of estrone and estradiol-17β to rat alpha-fetoprotein is demonstrated for the first time in embryo, immature and adult rat sera as well as in fetal and adult human sera. The competitive character and the narrow specificity of this inhibition effect is shown. The major compound responsible for this activity is isolated by successive column Sephadex LH₂₀ and thin layer chromatography : it is characterized as a nonpolar, nonphenolic, dialysable and thermostable substance, unreactive towards anti-estrone and anti-estradiol-17β anti-bodies. The possible biological role of an endogenous non-estrogen ligand of rodent fetoproteins is discussed.     

Purification and properties of mannitol dehydrogenase from Agaricus bisporus sporocarps

Mannitol dehydrogenase (mannitol: NADP⁺ 2-oxidoreductase: EC 1.1.1.138) was isolated from Agaricus bisporus by fractionation with protamine sulphate and (NH₄)₂SO₄, followed by chromatography on DEAE-Sephadex, then by affinity and gel chromatography. The products of enzyme reaction were identified by GLC and TLC. K_m, optimum pH, MW and pI of the enzyme as well as the influence of temperature, ions and inhibitors on enzymic activity were determined. In the sugar reducing reaction, the enzyme was specific for fructose but, in the reverse direction, some structurally related polyols could substitute for mannitol. The enzyme was very sensitive to alterations in the NADP⁺/NADPH ratio. The results are discussed in relation to the possible role of mannitol dehydrogenase in fungal metabolism.     

Light-harvesting pigment-protein complex deficiency in Hosta (Liliaceae)

A yellow-leaved plastome mutant of Hosta (Hosta sieboldii Ingram complex, Liliaceae) known as Wogan Gold lacks normal granal stacks, but has numerous stroma lamellae extending throughout the chloroplast. The chlorophyll a/b ratio is 0.76 in the mutant and 2.9 in wild type. The mutant contains a qualitatively normal pattern of other photosynthetic co-pigments. SDS-polyacrylamide gel electrophoresis showed a deficiency in the photosystem (PS) II light-harvesting complex. Since PS II is localized mainly in the granal region, the absence of the light-harvesting complex may explain the loss of granal stacking in this mutant.Abbreviation PS photosystem     

Increased Neopterin Levels in Brains of Patients with Human Immunodeficiency Virus Type 1 Infection

Postmortem levels of native neopterin (D-erythro-neopterin) were measured in cerebral cortical samples from 44 human immunodeficiency virus type 1-infected and eight uninfected, nonneurological control patients. Cerebral cortical gray and white matter neopterin levels for the controls ranged from 0.5 to 7.2 pmol/mg of protein in contrast to neopterin levels in brains of the virus-infected patients, which frequently were more than threefold and occasionally more than 30-fold higher than mean control levels. Cortical neopterin levels did not correlate with severity of the acquired immunodeficiency syndrome dementia complex, but subcortical levels correlated with the presence of active human immunodeficiency virus type 1 infection, as reflected by pathological evidence of multinucleated giant cell encephalitis. Evidence of opportunistic cytomegalovirus infections in approximately 25% of the human immunodeficiency virus type 1-infected patients was associated with enhanced levels of neopterin in frontal cortex.