Enzymes of the jejunal enterochromaffine cells in man

Summary A study of enzymatic equipment of enterochromaffine cells (e.c.) in jenual biopsies obtained with a Crosby capsule in normal humans and patients with nontropical sprue was undertaken. The following enzymes were demonstrated: alkaline phosphatase and adenosine triphosphatase (cell membrane), acid phosphatase (corpuscular), non-specific esterase (diffuse and corpuscular, predominantly eserine resistant, in corpuscular localization E 600 resistant), DPN- and TPN-diaphorases and dehydrogenases of lactic acid, malic acid, isocitric acid, glucoso-6-phosphoric acid, succinic acid, -hydroxybutyric acid and -glycerophosphoric acid. Enzyme activities were not equal in all cells suggesting some type of secretory cycle. In most patients with untreated nontropical sprue or with the disease in relapse e.c. were more numerous and hypertrophic with elevated activities of non-specific esterase and acid phosphatase. Implications of these results are briefly discussed.With 8 Figures in the Text, of which 2 in Colour     

Heterogeneous production of laccase by mycelium of white-rot fungi

Mycelium of white-rot fungi secretes laccase into the medium. It was found by cultivation on malt-agar plates that the mycelium does not produce laccase equally in all its parts. The youngest hyphae at the margins of the colony represent usually the maximum producers, whereas older hyphae produce less or none at all. An exception here isCollybia velutipes which is the weakest producer of laccase of all the fungi studied and where only the older hyphae begin to secrete it. Manometric estimation of laccase showed that maximum specific activity of laccase is achieved at the boundary between the phases of initial and linear growth and i₁₁ some cases during the first half of linear growth. Ageing of the mycelium characterized by certain changes in its metabolism is reflected in changes of enzyme production by fungal hypha of different age.     

Factors affecting the accuracy of chlorophylla andb determination by means of their paper chromatographic separation and colorimetric measurement in eluates

Quantitative determination of chlorophyll a and β can be made by paper chromatography of acetone extracts of plant material with colorimetric measurement of the eluates from the separated zones. From the suitable solvent systems which give adequate separation of the pigments at a distance of 20 cm. from the start,Hager's mixture (1955) separates the chlorophylls better than the toluene-isopropanol (400: 1 v/v.) mixture, which, however, is better for the separation of carotenoids. Twice the amount of chlorophyll is separated on Whatman 31 ET paper, equally well and with the same time of development, as on Whatman No. 3 paper, on which it is possible to separate a maximum of about 15 μg of chlorophyll pigments per 1 em. start length. Losses on elution are, however, higher on using Whatman 31 ET paper. In plants with a high chlorophyllase activity, the error of determining chlorophyll a andb is greatly reduced if the leaves are placed for 1 min. in boiling water before extraction. For elution of chlorophylla andb from paper it is better to use anhydrous acetone, for chlorophyllides 80% acetone. A comparison of the procedure investigated with the method of two-wave length spectrophotometric measurement of crude acetone extracts showed that in view of the average 10% loss, the chromatographic method is hardly suitable for determining the absolute amounts of chlorophylla andb, although the relation (a/b) can be determined with similar precision by both methods. Moreover, in view of the greater amount of work involved the chromatographic method can only be recommended for confirming the results of spectrophotometrie determination. Quantitative determination of chlorophylls from the area of the spot or from the "R_F" value can only be of an informative character.     

Flechtensystematische Studien VI. Die GattungSagiolechia Massal.

Eine taxonomische Studie über die GattungSagiolechia Massal. als wieter Teil einer Revision der FamilieGyalectaceae sensuZahlbruckner wird vorgelegt.     

Biomass partitioning in twoCalamagrostis villosa stands on deforested sites

Calamagrostis villosa stands occurring in areas deforested by air-pollution impact in the Moravian-Silesian Beskydy Mountains were characterized by a high dry mass of total underground biomass (3 300 g. m^?2—the slope site, 2 850 g. m^?2—the flat site). The percentage of living roots and rhizomes in total underground biomass was very high (about 70%). The total aboveground biomass was respectively, 321 g.m^?2 (the slope site) and 726 g. m^?2 (the flat site). In unstabilized habitats on steep slope, the higher plant biomass produced was allocated to a more developed root system.     

Apoptosis and nutrition: Involvement of amino acid transport system in repression of hybridoma cell death

Mouse hybridoma cells cultured on the verge of starvation-induced apoptosis, i.e. in a medium diluted with saline, proved to serve as a sensitive screening system for apoptosis-suppressing activity of nutrient medium components. Conventional amino acid mixtures were found to suppress the starvation-induced apoptosis, whereas a vitamin mixture was ineffective. (Frank F (1995) Biotechnol. Bioeng. 45: 86–90). Recent experiments showed that suppression of apoptosis, and concurrent resumption of growth, could be achieved by addition of single substances at millimolar concentrations. The set of active substances included certain coded L-amino acids (glycine, alanine, serine, threonine, proline, asparagine, glutamine, histidine), non-coded amino acids (-alanine, taurine, 4-aminobutyric acid), and a non-metabolizable analogue (2-aminoisobutyric acid). This finding shows that some amino acids do not act solely as nutrients, but also as specific signal molecules. The specificity of the effect points to the involvement of adaptively regulated amino acid transport systems A and N in maintaining the balance between triggering and suppression of starvation-induced apoptosis.     

Calcium distribution and exchange in the pregnant and post partum rabbit uterus

Calcium content and distribution of the 25-day pregnant (PR) and post partum (PP) rabbit uterus was studied by atomic absorption spectrophotometry and 45Ca determination. Total Ca content [2.28 +/- 0.28 (PR) and 2.19 +/- 0.12 (PP) mM/kg wet wt] extracellular [1.21 +/- 0.09 (PR) and 1.25 +/- 0.11 (PP) mM/kg wet wt] cellular [1.07 +/- 0.08 (PR) and 0.94 +/- 0.09 (PP) mM/kg wet et], total exchangeable [1.86 +/- 0.11 (PR) and 1.84 +/- 0.09 (PR) mM/kg wet wt] and inexchangeable [0.43 +/- 0.05 (PR) and 0.35 +/- 0.04 (PP) mM/kg wet wt] Ca fractions were identical in the two extreme endocrinological conditions. In contrast compartment size and rate constant of different exchangeable Ca fractions determined by kinetic analysis of 45Ca desaturation "urves (curve-peeling tecnique and computer method), revealed significant differences between PR and PP uteri. Two exchangeable phases could be identified in both endocrinological states. The rate constants of both phases of efflux were significantly higher in the PP (alpha 1 = 0.173 +/- 0.02 min-1; alpha 2 = 0.023 +/- 0.001 min-1) than in the PR uterus (alpha 1 = 0.099 +/- 0.01 min-1; alpha 2 = 0.018 +/- 0.01 min-1). Compartment size of phase 1 (fast component) was significantly higher in the PR (1.13 +/- 0.1 mM/kg wet wt) than in the PP uterus (0.77 +/- 0.06 mM/kg wet wt). In contrast, compartment size of phase 2 (slow component) was significantly smaller in PR than in PP uterine strips (0.74 +/- 0.06 and 1.08 +/- 0.11 mM/kg wet wt). The last portion of desaturation curves represents efflux from one homogenous compartment. The present results suggest that endocrinological control of the rabbit myometrium is linked to the regulation of the binding of a superficial exchangeable Ca fraction.     

Production of rhodomycins inStreptomyces griseoruber 4620

The strainStreptomyces griseoruber 4620 produces, besides the anthracycline antibiotics beromycins, some other anthracyclines of the rhodomycin type. Twelve isolates exhibiting a higher antibiotic activity (up to 2.5×), as compared to the parent strain, were obtained after a spontaneous selection. The following species were isolated from the hydrolysate of mycelial extract: β-rhodomycinone, β-isorhodomycinone, α₂-rhodomycinone and 10-deoxy-β-rhodomycinone, which has not yet been described.     

On the concept of biomathematics

The increasing complexity of biological problems and the increase of mathematical means to handle them on the one hand, and the possibility of automatized computation at the other, necessitate a revaluation of the present interactions between biology and mathematics; in this connection interrelations occur which can be divided into three kinds: mathematical biology, biological mathematics, and general biomathematics or methodology of the biomathematical sciences, by which are meant those scientific branches which arise from the said interactions.     

Comparative response ofPisum sativum nodulated with indigenous soilRhizobium populations and/or co-inoculated with aRhizobium leguminosarum strain

No significant differences in the acetylene-reducing activity and evolution of H₂ and CO₂ nodulated roots ofPisum sativum inoculated with soilRhizobium populations from two soils with different acidities (Ruzyně soil 7.6; Lukavec soil 4.9) were observed.Rhizobium population from Lukavec soil formed nodules, exhibiting a higher H₂ evolution. Co-inoculation with the Hup⁺ strain 128C30 (7×10⁷ cells per seedling) eliminated, to some extent, the effect of soil populations on physiological activity. Translated by Č. Novotny