Use of zeolite to control ammonium in Bacillus amyloliquefaciensα-amylase fermentations

 Both synthetic and natural ammonium-sorbing zeolite were used to control the NH⁺ ₄ level in Bacillus amyloliquefaciens cultures producing extracellular α-amylase. The addition of biochemically inert calcium aluminosilicates significantly increased the yield of the enzyme. A simple mathematical model explaining the mechanism has been formulated and its parameters estimated. Received: 1 August 1995/Received revision: 20 October 1995/Accepted: 24 October 1995     

High elevation coniferous vegetation of Guatemala

A phytosociological study of the juniper (locally called huito), pine (locally called sacch), pine-alder and fir forests of the Sierra de los Cuchumatanes and Cadena Volcánica in Guatemala was carried out. The Zürich-Montpellier approach was followed. In total 119 relevés were sampled and the data were organised in phytosociological tables to distinguish vegetation clusters. TWINSPAN was used to evaluate major differences among plant communities. Seven zonal plant communities were distinguished and described, namely: (1)Relbunium microphyllum-Agrostis tolucensis, (2)Werneria nubigena-Agrostis exserta, (3)Lachemilla vulcanica-Pinus hartwegii, (4)Holodiscus argenteus-Pinus hartwegii, (5)Hypnum cypressiforme-Juniperus standleyi, (6)Agave hurteri-Alnus firmifolia and (7)Sabazia pinetorum-Abies guatemalensis. This paper provides a thorough floristic characterisation of each community and outlines the major anthropogenic activities. To conclude, ecologic and floristic (dis)similarities between plant communities of the study area and those of Central Mexico, like the different altitudinal distribution of fir forests and the establishment of mid-successional communities such as theAgave hurteri-Alnus firmifolia were discussed.     

Flocculation of industrial and laboratory strains ofSaccharomyces cerevisiae

Summary A comparative study has been made of different laboratory and industrial wild-type strains ofSaccharomyces cerevisiae in relation to their flocculation behavior. All strains were inhibited by mannose and only one by maltose. In regard to the stability of these characters in the presence of proteases and high salt concentrations, a relevant degree of variation was found among the strains. This was to such an extent that it did not allow their inclusion in the Flol or NewFlo phenotypes. Genetic characterization of one wild-type strain revealed that the flocculation-governing gene was allelic toFLO1 found in genetic strains.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.     

Interrelationships between vesicular-arbuscular mycorrhiza and rhizosphere microflora in apple replant disease

Phytotoxic micromycetes appear to be responsible for the apple replant disease (ARD). This was suppressed by the inoculation of apple-tree seedlings with some species of vesicular-arbuscular mycorrhizal (VAM) fungi—Glomus fasciculatum andG. macrocarpum. After the inoculation, growth of apple-tree seedlings improved in dependence on the type of soil, on VAM fungus species and on the ARD appearance. After 12-month cultivation, plant biomass (height, shoot and root dry masses) was markedly increased by inoculation withG. fasciculatum. Similarly, the numbers of colony forming units per unit soil (CFU) of phytotoxic micromycetes and of diazotroph bacteria (associative dinitrogen-fixing bacteria) in the rhizosphere was affected; CFU of phytotoxic micromycetes decreased, whereas CFU of the genusAzospirillum was higher. These bacteria could also serve as antagonists against phytotoxic micromycetes. It is also suggested that the ratio of CFU of diazotroph bacteria to CFU of phytotoxic micromycetes can be used as an indicator of the degree of ARD. It may be assumed that the use of some VAM fungi can replace the chemcial treatment of the soil with ARD.     

Poly(3-hydroxybutyrate) granules ofBacillus megaterium

Cells ofBacillus megaterium contain 35–45% of poly(3-hydroxybutyrate) (PHB) at the beginning of the stationary phase. This amount is only slightly affected by the medium composition. The PHB granules are spherical with the mean diameter of 1.15 μm.     

Application of the exploratory data analysis for evaluating the toxicity of chlorinated phenol derivatives by various cell models

Exploratory data analysis based on multivariate statistical analysis techniques was introduced as a new approach to expressing the toxicity of chemical substances at the simultaneous acceptance of various cell models. Using principal component analysis and cluster analysis methods the toxicity of chlorinated phenol derivatives on employing some of the cell models (chlorococcal algae, cyanobacteria, bacteria, micromycetes, plant and animal cells) was characterized. The previous empirical experience that the toxicity of chlorinated phenol derivatives will increase with a growing degree of chlorination and that the presence of the methoxy group will cause a lowering of the toxic effect was demonstrated. The relationship between groups of tests used was presented.     

Lectins as markers of rumen epithelial cell differentiation

Summary Lectins of different carbohydrate specificities (GNA (Galanthus nivalis), con A (Canavalia ensiformis), VFL (Vicia faba), PSL (Pisum sativum), LCA (Lens culinaris), PNA (Arachis hypogaea; with or without prior neuraminidase treatment), WGA (Triticum vulgare), SBA (Glycine max), UEA-I (Ulex europaeus), LPA (Limulus polyphemus), BS-I B₄ (Bandeiraea simplicifolia, isolectin B₄)) were explored for use as differentiation markers of rumen epithelial cellsin vivo andin vitro. Lectins specific for mannose (GNA), mannose/glucose (con A, VFL, PSL and LCA),N-acetylglucosamine (WGA) or forN-acetylneuraminic acid (LPA) reacted generally with all types of rumen epithelial cell from both rumen tissue and cell culture. They were, therefore, not suitable markers of epithelial differentiation. SBA was unsuitable because, although it reacted with both tissue and cultured rumen epithelial cells, it was also bound to non-stratified areas of primary rumen epithelial cell cultures. Both BS-I B₄ and PNA (after neuraminidase treatment) had to be ruled out because they did not react with differentiated rumen tissue epithelial cells, although they did bind to both stratified and non-stratified cultured cells. In contrast, UEA-I reacted strongly with differentiated rumen epithelial cells both from rumen tissue and cell cultures and therefore appears to be a good general marker for rumen epithelial cell differentiation.     

Validation of the cumulative or replicate NAA method for the determination of trace elements in biological materials

Biological Trace Element Research - To make the best use of time and facilities, a neutron activation system, fully automatic, including spectrum and data processing, to be used with short-lived...     

Paracuaria hispanica n. sp. (Nematoda: Acuariidae), a stomach parasite of the pyrenean desman Galemys pyrenaicus Geoffr. (Insectivora: Talpidae), with a redefinition of the genus Paracuaria Rao, 1951

Adult and fourth-stage larvae of Paracuaria hispanica n. sp., from the stomach of the Pyrenean desman Galemys pyrenaicus Geoffroy (Insectivora: Talpidae) in northern and central Spain, are described. The new species differs from the other members of the genus Paracuaria (P. adunca and P. soricis), among other morphological details, in its smaller body and spicule sizes, the presence of a cuticular ring around the tip of the female tail, and the existence of lateral alae running longitudinally along its body from the cervical region to the tail. In view of the latter feature, the genus Paracuaria is redefined. The fourth stage larva of the new species is distinguished from that of P. adunca by its monocuspid deirids. P. hispanica occurred in 45% of the 20 host specimens examined.