The grassland communities of the southeastern basin of the Labe river 2. Synecology

This part of the study, referring to the previous syntaxonomic part (Ková? 1981), presents the results of a synecological examination of nine grassland communities of the Labe river basin covering roughly the following gradient of the alluvial hydrosere: theCerastio arvensi-Festucetum trachyphyllae trifolietosum pratensis, theArrhenatheretum elatioris typicum, theAlopecuretum pratensis, theStellario-Deschampsietum caespitosae phalaridetosum, theSerratulo-Festucetum commutatae, theMolinietum coeruleae brometosum, theAngelico-Cirsietum oleracei, theCaricetum gracilis typicum, theCaricetum buekii. The long-term study of ground-water level fluctuations showed their close connection to other characteristics of the meadow soils (soil type, moisture content, granulometric composition, capillary water-holding capacity, porosity, acidity, mineral nutrient contents, microbial activity, soil temperature) as well as to the development and distribution of the grassland communities associated with ecosystems of river alluvia. The formation and dynamics of the vegetation in the large river floodplain (at present exposed to the impact of far-reaching hydrological alteration) are explained as a consequence of changes in the natural ecocycles supporting the long-term stable character of the large river basin within the landscape.     

Estimation of the above-ground biomass of the herb layer in forest communities

The paper deals with the estimation of maximum above-ground herb-layer biomass in selected forest communities of the Malé Karpaty Mts., (Lesser Carpathians) SW. Slovakia. Use was made of a combined method of indirect sampling and phytocenological relevés, and the following values were ascertained: 41 kg/ha in theLuzulo-Fagetum (276 kg/ha if mosses included), 691 kg/ha in theCarici pilosae-Carpinetum, 364 kg/ha in theDentario-Fagetum, 476 kg/ha in theAceri-Carpinetum, and 1364 kg/ha in theStellario-Alnetum. The results are discussed and compared with earlier data published in the literature.     

Taxonomic significance of floral pigments in linum (Linageae)

Floral pigments of 30 taxa, representing five informally ranked subgeneric complexes(Linum schiedeanum, L. virginianum,L. neomexicanum, L. sulcatum, andL. rigidum) of yellow-flowered North American flaxes, were examined by paper chromatography. Earlier studies, based on comparative gross morphology, chromosomal complements, and pollen structure, led to the conclusion that members of theL. schiedeanum complex may be the most primitive and that theL. virginianum, L. neomexicanum, andL. rigidum complexes may have been derived independently, the latter via a taxon similar toL. sulcatum. Data from both carotenoids and flavonoids support this scheme. Spectral analysis reveals the exclusive presence of the Β-carotenoid, violaxanthin, in the X.schiedeanum, L. virginianum, L. neomexicanum, andL. sulcatum com-Taxa of theL. rigidum complex, with the exception ofL. subteres, possesplexes. exclusively the α-carotenoids, lutein and its 5, 6-monoepoxide.L. subteres, in its production of violaxanthin, provides a chemical link to the other complexes, though possession of several species-specific flavonoids suggests an early divergence from other members of theL. rigidum complex. Distinctions in the Chromatographic patterns of quercetin, luteolin, and other flavonoid compounds were found among the five groups. In general the loss of flavonoid pigments may be correlated with increased morphological specialization. Identical patterns in certain species of theL. schiedeanum andL. virginianum complexes support the presumed relationship between these two groups.     

Two interesting algae from Czech reservoirs

Paulschulzia pseudovolvox (Schulz)Skuja, a member of theTetrasporales, is recorded for the first time for Czechoslovakia.Amphidinium radiatum Javorn., a member of theGymnodiniales is recognized. Further information about its variability is supplemented. The algae were studied in two reservoirs.     

Regulation of acid phosphatases in anAspergillus niger pacC disruption strain

AnAspergillus niger strain has been constructed in which the pH-dependent regulatory gene,pacC, was disrupted. ThepacC gene ofA. niger, like that ofA. nidulans, is involved in the regulation of acid phosphatase expression. Disruptants were identified by a reduction in acid phosphatase staining of colonies. Southern analysis demonstrated integration of the disruption plasmid at thepacC locus and Northern analysis showed that the disruption strain produced a truncatedpacC mRNA of 2.2 kb (as compared to 2.8 kb in the wild type). The strain carrying thepacC disruption was used to assign thepacC gene to linkage group IV; this was confirmed by CHEF electrophoresis and Southern analysis. This strain further allowed us to determine which extracellular enzyme and transport systems are under the control ofpacC inA. niger. Expression of theA. niger pacC wild-type gene and the truncatedpacC gene showed that, in contrast to the auto-regulated wild-type expression, which was elevated only at alkaline pH, the truncatedpacC gene was deregulated, as high-level expression occurred regardless of the pH of the culture medium. Analysis of the phosphatase spectrum by isoelectric focussing and enzyme activity staining both in the wild-type and thepacC disruptant showed that at least three acid phosphatases are regulated by thepacC. For the single alkaline phosphatase no pH regulation was observed.     

Restriction fragment length polymorphism and chromosome mapping of a mouse homeo box gene,Hox-2.1

Restriction endonuclease fragment length polymorphisms (RFLPs) were found using the cDNA probe Hox-2.1 for the homeo box-2.1 gene in the mouse. Polymorphism was detected in restriction patterns generated by fragments fromHindIII digestion. The great majority of laboratory strains of mice carries theHox-2.1 ^a allele. Only two laboratory strains carry theHox-2.1 ^b allele. Among strains of wild origin, the European subspecies (Mus m. domesticus, M. m. brevirostris, andM. m. musculus) and some Asian subspecies (M. m. castaneus) carry theHox-2.1 ^a allele. The subspecies from Far Eastern countries (M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai) carry theHox-2.1 ^ballele. Using the RFLP, theHox-2.1 gene was mapped on chromosome 11. Three-point cross test data showed that the recombination frequency is 29.6% between theHba and theHox-2.1 genes and 23.5% between theHox-2.1 and theEs-3 genes. The gene order ofHba-Hox-2.1-Es-3 has been confirmed.     

Heathland vegetation of the northern-central part of the Iberian Peninsula

Heathland vegetation of northern Spain, included in theCalluno-Ulicetea, was studied using a set of 802 phytosociological relevés. The existing syntaxonomy has been tested and most of the types (associations and subassociations) fit satisfactorily with the observed groupings. Two main problems were encountered within theUlex dominated communities of the Cantabrian fringe and the Castilian-Cantabrian heathland communities. Both groups of communities were subject to ordination in order to clarify relationships between them. For the former group, ordination suggests that three associations can be distinguished: theUlici-Ericetum vagantis (lowlands up to the submontane belt), theVaccinio-Ulicetum gallii for the communities of higher altitudes (montane belt) and theUlici-Ericetum ciliaris (hygrophilous heathlands). The Castilian-Cantabrian heathlands show a variable Mediterranean influence and have a dispersed distribution due to lithological conditions. This results in the distinction of two new associations, viz. theArctostaphylo crassifoliae-Daboecietum cantabricae (marly, water-retaining soils) and theEricetum scopario-vagantis (sandy soils). A complete classification of theCalluno-Ulicetea in the studied area and short ecological and biogeographical diagnoses are given.     

ASPECTS OF THE INTEGRATION OF THE TAXONOMY OF LICHENIZED AND NON-LICHENIZED PYRENOCARPOUS ASCOMYCETES

The integration of the taxonomy of lichenized and non-lichenized pyrenocarpous ascomycetes is still in progress. Within this group, at least 12 lichenization events, three re-lichenizations and at least 24 de-lichenization events, are supposed to have occurred during evolution. This is evident from the increasing amount of information regarding phylogeny and classification of pyrenocarpous fungi. The total number of lichenization events, including re- and de-lichenization, within all fungi is estimated to be at least 100. However, the vast majority of the pyrenocarpous lichens are concentrated in a few relatively large, presumably monophyletic, groups. In some cases, proposed integrations have proven to be untenable, for exampleMicrotheliopsisand with theHerpotrichiellaceae,Flavobatheliumwith theDimeriaceaeand most notably theNormandinathallus with the basidio-mycetes and its ascocarps withSphaerulinain theMycosphaerellaceae. The same is true for many cases where lichenized taxa were unwittingly included in otherwise non-lichenized groups, such asDidymosphaeriaandMassarina, or even described in new, presumably non-lichenized, genera likeHolstiella,StarbaeckiellaandTitanella.     

Communities ofAnthriscus caucalis andAsperugo procumbens in Slovakia

Two ruderal seam communities, theLactuco-Anthriscetum caucalidis andAhthrisco-Asperugetum procumbentis, are described in Slovakia. Both communities occur on loess in regions of warm and dry climate. Besides the species of theGalio-Alliarietalia, those of theSisymbrietalia andArtemisietalia design the floristical composition of the communities. Numerical classification and ordination techniques were adopted to clarify systematic relations of the communities and show the structure of the revealed clusters. A comparison of the results of the numerical methods and the syntaxonomical table synthesis has been performed and briefly discussed.     

Indirect evidence of alteration in the expression of the rDNA genes in interspecific hybrids betweenDrosophila melanogaster andDrosophila simulans

Crosses betweenDrosophila melanogaster females andD. simulans males produce viable hybrid females, while males are lethal. These males are rescued if they carry theD. simulans Lhr gene. This paper reports that females of the wild-typeD. melanogaster population Staket do not produce viable hybrid males when crossed withD. simulans Lhr males, a phenomenon which we designate as the Staket phenotype. The agent responsible for this phenomenon was found to be the StaketX chromosome (X ^mel ,Stk). Analysis of the Staket phenotype showed that it is suppressed by extra copies ofD. melanogaster rDNA genes and that theX ^mel ,Stk chromosome manifests a weak bobbed phenotype inD. melanogaster X ^mel ,Stk/0 males. The numbers of functional rDNA genes inX ^mel ,Stk andX ^mel ,y w (control) chromosomes were found not to differ significantly. Thus a reduction in rDNA gene number cannot account for the weak bobbedX ^mel ,Stk phenotype let alone the Staket phenotype. The rRNA precursor molecules transcribed from theX ^mel ,Stk rDNA genes seem to be correctly processed in both intraspecific (melanogaster) and interspecific (melanogaster-simulans) conditions. It is therefore suggested that theX ^mel ,Stk rDNA genes are inefficiently transcribed in themelanogaster-simulans hybrids.     

Vegetation on anthropogenic metalliferous soils in the Eastern Alps

A syntaxonomic revision of vegetation of anthropogenic metalliferous habitats (mine spoils of lead, zinc and copper mining) in the Eastern Alps (Austria, Germany, Italy and Slovenia) was made. The communities studied belong to theThlaspietea rotundifolii (Linaria alpina-Cerastium uniflorum comm.,Papaveri kerneri-Thlaspietum kerneri, Violetum dubyanae, Thlaspietum cepaeifolii, Thlaspietum rotundifolii, Scrophulario juratensis-Erysimetum sylvestris, Minuartia gerardii-Silene glareosa comm.,Epipactido atrorubentis-Silenetum glareosae andSileno alpestris-Moehringietum muscosae) and to theAsplenietea trichomanis (Sileno rupestris-Asplenietum). There is neither floristic support nor syntaxonomic justification for the concepts of theGalio anisophylli-Minuartion vernae, theVioletalia calaminariae and theVioletea calaminariae in the Eastern Alps. These units should be included within theThlaspion rotundifolii, Thlaspietalia rotundifolii andThlaspietea rotundifolii, respectively.     

Characterization of type II protein secretion (xcp) genes in the plant growth-stimulatingPseudomonas putida,strain WCS358

InPseudomonas aeruginosa, the products of thexcp genes are required for the secretion of exoproteins across the outer membrane. Despite structural conservation of the Xcp components, secretion of exoproteins via the Xcp pathway is generally not found in heterologous organisms. To study the specificity of this protein secretion pathway, thexcp genes of another fluorescent pseudomonad, the plant growth-promotingPseudomonas putida strain WCS358, were cloned and characterized. Nucleotide sequence analysis revealed the presence of at least five genes, i.e.,xcpP, Q, R, S, andT, with homology toxcp genes ofP. aeruginosa. Unlike the genetic organization inP. aeruginosa, where thexcp cluster consists of two divergently transcribed operons, thexcp genes inP. putida are all oriented in the same direction, and probably comprise a single operon. Upstream ofxcpP inP. putida, an additional open reading frame, with no homolog inP. aeruginosa, was identified, which possibly encodes a lipoprotein. Mutational inactivation ofxcp genes inP. putida did not affect secretion, indicating that no proteins are secreted via the Xcp system under the growth conditions tested, and that an alternative secretion system is operative. To obtain some insight into the secretory pathway involved, the amino acid sequence of the N-terminus of the major extracellular protein was determined. The protein could be identified as flagellin. Mutations in thexcpQ andR genes ofP. aeruginosa could not be complemented by introduction of the correspondingxcp genes ofP. putida. However, expression of a hybrid XcpR protein, composed of the N-terminal one-third ofP. aeruginosa XcpR and the C-terminal two-thirds ofP. putida XcpR, did restore protein secretion in aP. aeruginosa xcpR mutant.     

Neue Bodenalgen aus den Dolomiten

Five new genera and five new species of alpine soil algae from S. Tyrol are described from cultures and figured. One of them belongs to theXanthophyceas:Heterothrix sessilis, spec. nova, the remaining to theChlorophyceae:Scotiellopsis rubescens, gen. et spec. nov.,Pseudodictyochloris dissecta, gen. et spec. nov.,Chlorozebra cohaerens, spec. nova,Neochloris bilobata, spec. nova,Myrmecia astigmatica, spec. nova,Trochisciopsis tetraspora, gen. et spec. nov.,Pseudotrochiscia areolata, gen. et spec. nov.,Stichococcus undulatus, spec. nova, andHormidiospora verrucosa, gen. et spec. nov.     

Comparison of the primary structure ofwaxy proteins (granule-bound starch synthase) between polyploid wheats and related diploid species

Thewaxy proteins encoded by the genomes A, B, and D in polyploid wheats and related diploid species were isolated by SDS-PAGE. The N-terminal amino acid sequences of mature proteins and V8 protease-induced fragments were determined. A total of five amino acid substitutions was detected in these sequences, which represent about 10% of the whole sequences of thewaxy proteins. A comparison of these sequences in polyploid wheats with those in related diploid species revealed the following: (i)waxy proteins encoded by the A genome of polyploid wheats were identical to that ofTriticum monococcum, (ii) thewaxy protein encoded by the B genome ofT. turgidum was identical to that ofT. searsii, but differed from those ofT. speltoides andT. longissimum by one amino acid substitution, (iii) thewaxy protein encoded by the B genome ofT. aestivum differed from that encoded by the B genome ofT. turgidum by one amino acid substitution, and (iv) thewaxy protein encoded by the D genome ofT. aestivum was identical to that ofT. tauschii.