Neurospecific and neuron-specific enolase levels in human nerve tissue at early stages of embryogenesis

Neurospecific and neuro-nonspecific isozymes of glycolytic enzyme enolase known to be molecular markers of neuronal and glial cells respectively were isolated from human brain. Using immunoenzyme assay, the content of these proteins was measured in the brain of 7-13-week human embryos and adult subjects. The content of both isoenzymes gradually increases attaining constant level in 10-13-week embryos. Relative content of neuro-nonspecific enolase in the brain of 10-13-week embryos is 1 1/2 times higher than that in adults, whereas the content of neurospecific enolase amounts only to 2% of its level in the adult brain.     

Nomenclatural remarks on the association names ofNardus stricta-rich communities in Central Europe

The present paper gives comments on the nomenclature of associations ofNardetalia andNardo-Caricion rigidae from Central Europe. A brief list of important homonyms and ambiguous names is added.     

Fractionation of eukaryotic DNA in a pulsating electrical field. I. Detection and properties of discrete DNA fragments]

The fractionation of eukaryotic DNA by field inversion gel electrophoresis results in the appearance of discrete DNA-fragments. The set of these fragments is similar to that of different eukaryotic representatives and consists of various chromosomal DNAs, unified by size. The physical properties of DNA-fragments suggest that they can form multimeric structures due to the presence of sticky ends flanking discrete fragments. We suppose that the set of discrete DNA-fragments results in a specific cleavage of intact nuclear DNA and can reflect different levels of chromatin structural organization.     

Ethmoidal endocranium in primitive triassic amphibians

Three-dimensionally preserved and chemically prepared skulls and natural casts of representatives of the families Benthosuchidae, Melosauridae, and Capitosauridae yield data on the structure of the ethmoidal endocranium, i. e. of those nasal cranial structures that consisted originally of cartilage. This study demonstrates that the ethmoidal endocranium was principally a dorsoventrally compressed plate, pierced by a broad and oblique canal which communicated anteriorly with the outer dorsal surface by the fenestra endonarina and posteriorly with the mouth cavity by the fenestra endochoanalis(seu foris). The canal was very short, and housed the olfactory organ. The ethmoidal endocranium was connected with the palatoquadrate by the commissura quadratocranialis anterior; there was no lateral ethmoidal commissure, however, in older individuals the anterior section of the palatoquadrate might also contact the postchoanal part of the nasal endocranial skeleton.     

Effect of detergents on aspartate ammonia-lyase activity inEscherichia alcalescens

The effect of twelve detergents on aspartate ammonia-lyase activity of Escherichia alcalescens used for the production of L-aspartic acid was tested. Best permeabilization was found with Triton X-100, Slovafol 910 and Corona, a mixed commercial preparation. In contrast to Triton X-100 and Slovafol 910, a much narrower range of suitable concentrations was observed with Corona.     

Benzothiazolium salts—relationships between their structure,toxicity and effect on the plastid system ofEuglena gracilis

The effects of 41 benzothiazolium salts on Euglena gracilis were characterized with regard to the influence on growth and on chlorophyll synthesis, and to their ability to induce permanent loss of chloroplasts. Some salts induced white mutants of E. gracilis (the first benzothiazole derivatives with this activity). The relationship between the biological effect and chemical structure was confirmed and expressed quantitatively by means of Free - Wilson and Fujita - Ban analysis.     

Saprophytic production of Clavine alkaloids and activity of Hydroxymethylglutaryl-CoA reductase

In submerged Claviceps cultures the activity of hydroxymethylglutaryl-CoA reductase preceded the increase of alkaloid production and of sterol content. During the first alkaloid phase, cell mevalonate was involved in the biosynthesis of both alkaloids and steroids. In the second production phase, it was predominantly used for alkaloid synthesis. Hydroxymethylglutaryl-CoA reductase appears to be a suitable target for physiological manipulation to increase clavine alkaloid yields.     

Glutamicin CBII,a bacteriocin-like substance produced by

Corynebacterium glutamicum CBII, in the stationary phase of growth, was found to produce spontaneously a substance resembling bacteriocins by its bactericidal properties. This substance designated glutamicin CBII was observed to exhibit bactericidal activity against coryneform bacteria (12 species tested) but not against unrelated gram-positive (3) and gram-negative (3) bacteria, while its action on bacteria with no quite known relatedness to the coryneform group (14) was found to be variable. Glutamicin CBII was partially purified by precipitation with ammonium sulphate (70% saturation), selective heat precipitation and gel chromatography on Sepadex G-50. The antibacterial substance diffused through cellophane membrane with an approximate cut-off of 10000 dalton and its sedimentation coefficient was determined to be 1.1. S by ultracentrifugation. Heating at 100°C for 30 min had no effect on its activity. Glutamicin CBII was proved to be resistant to chloroform, trypsin, chymotrypsin, pronase, and subtilisin. According to its staining behaviour and ¹H NMR spectra it probably represents a glycoprotein containing only a minor protein component.

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Seasonal changes in the photosynthetic response ofMercurialis perennis plants from different light regime conditions

Curves relating net photosynthetic rate to irradiance [P(I) curve relation] were estimated and analysed inMercurialis perennis L. plants stemming from three forest (spruce, beech and ash) stands with different tree leaf canopy development and different light regime. The saturating irradiance (I_s) reached the highest values in plants of all three stands in spring (spruce forest: 438 W m⁻², beech forest: 440 W m⁻² and ash forest: 367 W m⁻²), it declined sharply in the middle of the growing season (283, 285 and 297 W m^-2, respectively) and this I_s level persisted until autumn. A pronounced dynamics in plants from spruce and beech forests made itself manifest also in the adaptation (I_a) and compensating (I_c) irradiances, respectively. After a sudden decline in summer, values in autumn were close to those of the vernal season. The most pronounced parameter, which optimally expressed the adaptation ofMercurialis perennis to various light conditions, was the photosynthetic efficiency (α) calculated as the slope of the linear part of the curve relating net photosynthetic rate to irradiance. At the time of the highest P_{N sat.} value in course of the growing season (August) (spruce forest: 100, beech forest: 98.7 and ash forest: 85.8 μg CO₂ m⁻² s⁻¹), R_D was in its minimum; in autumn P_{N sat.} reached the lowest values which corresponded to the most intensive R_D. It was found thatMercurialis perennis plants stemming from forest stands with different light conditions did not make use equally of the altering light conditions in the course of the growing season. By the underlying analysis of P(I) curves this rhizomatous perennial herb (geophyte) may be characterized as a shade tolerant species.