Mechanical transmission of beet yellows virus toChenopodium quinoa Willd. andChenopodium foliosum (Moench) Asch.

Beet yellows virus (BYV) was mechanically transmitted by sap from sugar-beet plants, infected with BYV, to the plants ofChenopodium quinoa Willd. and ofChenopodium foliosum (Moench) Asch. Mechanical transmission of BYV to the plants ofTetragonia expansa Murr. failed. Infectious material was homogenized in phosphate buffer with veronal and EDTA, pH 7–8. Experimental plants were darkened three days before infection and kept at a temperature of 5°C. Plants ofC. quinoa Willd. were decapitated. Back transmissions fromC. quinoa Willd. andC. foliosum (Moench) Asch. infected with BYV, to sugar-beet plants were carried out by the aveidMyzus persicae Sulz. These transmissions were positive. Filamentous particles of BYV, of an average length 1275 nm, were found in plants ofC. quinoa Willd. andC. Foliosum (Moench) Asch., infected with BYV.     

Notes on some African hepatic genera 1–5

The present study deals with five genera of hepatics in Africa, Isotachis Mitt., Anastrophyllum (Spruce) Steph., Tritomaria Schiffn. ex Loeske, Gymnocoleopsis (Schust.) Schust. and Lophozia (Dum.) Dum. All African populations of the genus Isotachis Mitt. are considered to be one species, I. aubertii (Schwaegr.) Mitt. Four species of Anastrophyllum (Spruce) Steph. (s.l.), A. auritum (Lehm.) Steph., A. piligerum (Nees) Spruce, A. subcomplicatum (Lehm. et Lindenb.) Steph. and A. minutum (Schreb.) Schust., and two species of Tritomaria Schiffn. et Loeske, T. camerunensis S. Arnell and T. exsecta (Schrad.) Schiffn. ex Loeske occur in Africa. Gymmocoleopsis multiflora (Steph.) Schust. represents a genus and species hitherto unreported for the African flora. Finally, five Lophozia (Dum.) Dum. species, L. argentina (Steph.) Schust., L. capensis S. Arnell, L. decolorans (Limpr.) Steph., L. hedbergii S. Arnell and L. tristaniana (S. Arnell) Váňa, are reported from central and southern Africa; two of these (L. argentina (Steph.) Schust. and L. decolorans (Limpr.) Steph.) represent the first reports from Africa.     

Chromosome counts and chromosome morphology of some selected species

In the years 1976–1981 we studied chromosome counts and karyotypic formulae of the following 29 species of plants from 41 localities (of these 6 from Bohemia, 32 from Moravia, 3 from Slovakia):Batrachium baudotii (Godron) F. W. Schultz,Chenopodium rubrum L.,C. polyspermum L.,C. murale L.,C. ficifolium Sm.,C. opulifolium Schrader ex DC. inLam. et DC.,C. strictum Roth [subsp.strictum, subsp.glaucophyllum (Aellen)Aellen inJust etAellen, subsp.striatiforme Uotila],Arenaria grandiflora L.,Illecebrum verticillatum L.,Spergula morisonii Boreau inDuchartre,Spergularia marginata (DC. inLam. et DC.)Kittel S. marina (L.)Griseb.,S. rubra (L.) J. etC. Presl,Silene conica L.,Sisymbrium loeselii L.,S. volgense Bieb. exE. Fourn.,S. orientale L. [subsp. orientale, subsp.macroloma (A. Pomel)Dvo?ák],S. officinale (L.)Scop.,Descurainia sophia (L.)Webb exPrantl inEngler etPrantl,Nasturtium officinale R. Br. inAiton,Barbarea arcuata (Opiz inPresl J. et C.)Reichenb.,Lunaria annua L.,Soldanella montana Willd.,S. carpatica Vierh. inUrban etGraebner,Lotus tenuis Waldst. etKit. exWilld.,L. uliginosus Schkuhr,Trigonella monspeliaca L.,Geranium sibiricum L.,Lactuca tatarica (L.)C. A. Meyer.     

ClassAsteretea tripolium on the territory of the former USSR and Mongolia

Higher syntaxa of the classAsteretea tripolium are reviewed. This class covers plant communities of the Euro-Asian continent on low- and medium-salinized soils with medium moisture conditions where perennial herbaceous plants (hemicryptophytes) of non-succulent character prevail. On the territory of the former USSR and Mongolia, the classAsteretea tripolium is represented by the following orders:Glauco-Puccinellietalia Beeftink etWesthoff inBeeftink 1962,Cirsietalia esculenti Mirkin etV. Golub exV. Golub ord. novus,Scorzonero-Juncetalia gerardii Vicherek 1973,Halerpestetalia Mirkin et al. exV. Golub ord. novus,Artemisio santonicae-Limonietalia gmelinii V. Golub etV. Solomakha 1988,Suaedetalia corniculatae V. Golub ord. novus. Superspecies and aggregations of species are used for the diagnosis of higher syntaxa.     

Ein Beitrag zur Nomenklatur sphinctozoider Schwämme (Porifera)

The sphinctozoid sponge generaFania Senowbari-Daryan 1990 andSpica Termier &Termier 1977 are preoccupied.Fania is replaced byFanthalamia nom. nov. andSpica by the younger synonymFistulispongia Termier &Termier 1977. The invalid subfamily name FaniinaeSenowbari-Daryan 1990 is replaced by Fanthalamiinae n. subfam. The invalid family and subfamily names SpicidaeTermier &Termier 1977 and SpicinaeSenowbari-Daryan 1990 respectively are replaced by FistulispongiidaeTermier atTermier 1977 and FistulispongiinaeSenowbari-Daryan 1990. The generaWaagenium de Laubenfels 1957 andCatubria Merla 1931 were previously overlooked.Waagenium DeLaubenfels 1957 is a younger synonym ofColospongia Laube 1865. The position ofCatubria Merla 1931 is uncertain. Most probablyCatubria is an alga.     

Exploring the allosteric mechanism of dihydrodipicolinate synthase by reverse engineering of the allosteric inhibitor binding sites and its application for lysine production

Dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) catalyzes the first committed reaction of l-lysine biosynthesis in bacteria and plants and is allosterically regulated by l-lysine. In previous studies, DHDPSs from different species were proved to have different sensitivity to l-lysine inhibition. In this study, we investigated the key determinants of feedback regulation between two industrially important DHDPSs, the l-lysine-sensitive DHDPS from Escherichia coli and l-lysine-insensitive DHDPS from Corynebacterium glutamicum, by sequence and structure comparisons and site-directed mutation. Feedback inhibition of E. coli DHDPS was successfully alleviated after substitution of the residues around the inhibitor’s binding sites with those of C. glutamicum DHDPS. Interestingly, mutagenesis of the lysine binding sites of C. glutamicum DHDPS according to E. coli DHDPS did not recover the expected feedback inhibition but an activation of DHDPS by l-lysine, probably due to differences in the allosteic signal transduction in the DHDPS of these two organisms. Overexpression of l-lysine-insensitive E. coli DHDPS mutants in E. coli MG1655 resulted in an improvement of l-lysine production yield by 46 %.     

Characterization of a recombinant l-rhamnose isomerase from Bacillus subtilis and its application on production of l-lyxose and l-mannose

The gene of an l-rhamnose isomerase (RhaA) from Bacillus subtilis was cloned to the pET28a(+) and then expressed in the E. coli ER2566. The expressed enzyme was purified with a specific activity of 3.58 U/mg by His-Trap affinity chromatography. The recombinant enzyme existed as a 194 kDa tetramer and the maximal activity was observed at pH 8.0 and 60°C. The RhaA displayed activity for l-rhamnose, l-lyxose, l-mannose, d-allose, d-gulose, d-ribose, and l-talose, among all aldopentoses and aldohexoses and it showed enzyme activity for l-form monosaccharides such as l-rhamnose, l-lyxose, l-mannose, and l-talose. The catalytic efficiency (k _cat/K _m) of the recombinant enzyme for l-rhamnose, l-lyxose, and l-mannose were 7,460, 1,013, and 258 M/sec. When l-xylulose 100 g/L and l-fructose 100 g/L were used as substrates, the optimum concentrations of RpiB were determined with 6 and 15 U/mL, respectively. The l-lyxose 40 g/L was produced from l-xylulose 100 g/L by the enzyme during 60 min, while l-mannose 25 g/L was produced from l-fructose 100 g/L for 80 min. The results suggest that RhaA from B. subtilis is a potential producer of l-form monosaccharides.     

Studien über dieJungermannioideae (Hepaticae) 6.Jungermannia Subg.Solenostoma: Europäische und nordamerikanische Arten

Dersechste Beitrag aus der Serie der vorbereiteten Studien über die SubfamilieJungermannioideae (Jungermanniaceae, Hepaticae) enthält die taxonomische Bearbeitung des Subg.Solenostoma (Mitt.)Amak. (GattungJungermannia L. emend.Dum.) in Europa (inkl. Kaukasus und Kleinasien) und Nordamerika. Im genannten Gebiet kommen 10 Arten vor, u. zw.J. caespiticia Lindenb.,J. caucasica Váňa,J. confertissima Nees,J. gracillima Sm.,J. handelii (Schiffn.)Amak.,J. jenseniana Grolle,J. lignicola (Schiffn.)Grolle,J. pyriflora Steph.,J. rubra Gott. exUnd. undJ. sphaerocarpa Hook. Die ArtJ. confertissima Nees (bisher alsSolenostoma levieri (Steph.)Steph. bezeichnet) gehört zu der SektionDesmorhiza Amak., alle anderen Arten gehören zu der SektionSolenostoma.     

d-Amino Acid-Induced Expression of d-Amino Acid Oxidase in the Yeast Schizosaccharomyces pombe

We investigated d-amino acid oxidase (DAO) induction in the popular model yeast Schizosaccharomyces pombe. The product of the putative DAO gene of the yeast expressed in E.?coli displayed oxidase activity to neutral and basic d-amino acids, but not to an l-amino acid or acidic d-amino acids, showing that the putative DAO gene encodes catalytically active DAO. DAO activity was weakly detected in yeast cells grown on a culture medium without d-amino acid, and was approximately doubled by adding d-alanine. The elimination of ammonium chloride from culture medium induced activity by up to eight-fold. l-Alanine also induced the activity, but only by about half of that induced by d-alanine. The induction by d-alanine reached a maximum level at 2?h cultivation; it remained roughly constant until cell growth reached a stationary phase. The best inducer was d-alanine, followed by d-proline and then d-serine. Not effective were N-carbamoyl-d,l-alanine (a better inducer of DAO than d-alanine in the yeast Trigonopsis variabilis), and both basic and acidic d-amino acids. These results showed that S. pombe DAO could be a suitable model for analyzing the regulation of DAO expression in eukaryotic organisms.     

Differentiation of strains of sugar beet yellows virus onTetragonia expansa Murr. and other indicator plants

Five different isolates of beet yellows virus were maintained without any changes in their properties onTetragonia expansa Murr. syn.T. tetragonoides Pall. for a long period of time. According to their characteristics and different properties especially in a diploid inbred line of sugar beet the isolates are considered to be strains of BYV and are classified into three groups: group of mild strains (the mild masked and mild strains), normal strains (the common strain) and necrotic strains (the severe necrotic and necrotic strains). The necrotic strains of BYV were relatively easily transmissible manually to sugar beet plants and other indicator species. The common strain can be transmitted to sugar beet,Chenopodium quinoa Willd. but not toC. capitatum L. Asch. Mild strains are transmissible with difficulty andC. quinoa is the only species which develops a larger number of local lesions after inoculation. In contrast to the mild masked and common strains it is manually transmissible toC. capitatum. The mild masked strain can not be transmitted to sugar beet.Nicotiana quadrivalvis Pursh. is not susceptible to mechanical inoculation with BYV. Aphid transmission withMyzus persicae (Sulz.) was positive in experiments with necrotic strains only. Mechanical transmission of BYV was successful also toC. foliosum (Moench) Asch.,C. murale L. andClaytonia perfoliata Donn. The last two species were susceptible to inoculation by aphids as well. Attempts to transmit the virus manually toT. expansa Murr. andC. giganteum Donn. failed.     

LignicolousHyphomycetes from Czechoslovakia 1.Brachysporium

Four species of the genusBrachysporium Sacc. emend.Mason etHughes are treated in this paper from Czechoslovakia:B. nigrum (Link)Hughes,B. obovatum (Berk.)Sacc. and two new species,B. abietinum Hol.-Jech. andB. brevius Hol.-Jech.     

Chromosome counts of some Cuban Angiosperms

Chromosome numbers are reported for 14 species collected in Cuba. The first chromosome records are reported forAlbizzia cubana Britton etWilson (2n=26),Atkinsia cubensis (Britton etWilson)Howard (2n=26),Caesalpinia violacea (Mill.)Standl. (2n=24),Colubrina ferruginosa Brongn. (2n=24). Chromosome numbers of the following species were confirmed:Albizzia lebbeck (L.)Benth. (2n=26),Canavalia maritima (Aubl.)Thouars (2n=22),Casuarina equisetifolia Forst. (2n=18),Cedrela mexicana M.J. Roem. (2n=56),Delonix regia (Bojer)Raf. (2n=28),Guazuma tomentosa H.B.K. (2n=16),Lysiloma bahamense Benth. (2n=26),L. latisiliqua (L.)Benth. (2n=26),Samanea saman (Jacq.)Merrill (2n=26),Thespesia populnea (L.)Soland (2n=26).     

Cytotaxonomic study ofTragopogon L. in czechoslovakia

Karyotypes ofTragopogon orientalis L. subsp.orientalis, T orientalis L. subsp.leiocarpos (Sauter)Trnka,T. pratensis L.,T. minor Miller,T. dubius Scop. subsp.dubius andT. dubius Scop. subsp.major (Jacq.)Vollmann were studied. The occurrence in Slovakia ofT. pratensis was karyologically proved.     

Foraminifera from the Silberberg Formation («Lower Oligocene») at Silberberg,near Helmstedt (Germany)

From the Silberberg Quarry, type locality of the Silberberg Formation (Martini &Ritzkowski 1968), some planktonic foraminifera are described:Globigerina officinalis Subbotina, Globigerina ouachitaensisHowe &Wallace,G. praebulloides leroyi Blow &Banner, G.praebulloides occlusa Blow &Banner which taxa are here suggested to form intergrading morphotypes within the range of variation of a population dominated byG. officinalis. In addition,G. cf.danvillensis Howe &Wallace is found. The planktonic fauna, together with some elements in the benthonic fauna, suggests a possible correlation with the Danville Landing Member of the Jackson Formation, Louisiana, traditionally ascribed to the Upper Eocene. There is some similarity with European Uppermost Eocene — Lower Oligocene faunas described by various authors. The Silberberg Formation was suggested to be a Neostratotype for the Latdorfian Stage of the Lower Oligocene byMartini &Ritzkowski (1968). It is suggested that the Silberberg Formation may well be coeval with the Upper Priabonian as proposed byCita 1969.     

Bemerkungen zu einigen balkanischenOxytropis-Arten

The present paper deals with the following three mountainOxytropis species:Oxytropis urumovii Jáv. inUrumov, an endemic species of the Pirin (Bulgaria);O. dinarica (Murb.) Wettst. distributed predominantly in Yugoslavia, andO. campestris which is common in the East Alps, but very rare in the Balkans. Three subspecies ofO. dinarica were distinguished: subsp.dinarica, subsp.weberi Chrtek etChrtková, and subsp.velebitica Chrtek etChrtková. In addition, a new combinationO. halleri Bunge exKoch subsp.korabensis (Kümmerle etJáv.)Chrtek etChrtková is given.     

A revision ofTaraxacum sect.Piesis (Compositae)

On the basis of allozyme and cultivation data, and of additional herbarium material, a taxonomic and nomenclatural revision ofTaraxacum sect.Piesis A.J. Richards exKirschner et?těpánek is provided. The section is made up of halophilous, sexually reproducing taxa. InT. stenocephalum Boiss. etKotschy,T. pindicum Kirschner et?těpánek, sp. nov., andT. perenne Kirschner et?těpánek, sp. nov., a tetraploid chromosome number has been recorded, representing the only known case of sexuality at the tetraploid level in the genus. The complex ofT. stenocephalum, includes some geographically and morphologically extreme populations treated as subspecies: subsp.gumusanicum (Soest)Kirschner et?těpánek, comb. nov., subsp.magnum Kirschner et?těpánek, subsp. nov., and subsp.daralagesicum (Schischk.)Kirschner et?těpánek, comb. nov. In addition toT. bessarabicum (Hornem.)Hand.-Mazz., a widely distributed Eurasian species,T. stenocephalum, a complex centred in Transcaucasia and Anatolia, andT. pachypodum H. Lindb., a North African endemic, four new species are described:T. salsum Kirschner et?těpánek, sp. nov., a diploid endemic confined to E Crimea,T. perenne Kirschner et?těpánek, sp. nov., a tetraploid sexual species known only from SW Crimea,T. pindicum Kirschner et?těpánek, sp. nov., a remarkable tetraploid endemic to the Pindos Mts., Greece, andT. salsitatis Kirschner, ?těpänek etYirdirimli, sp. nov., an Anatolian diploid species. Furthermore, a hybrid betweenT. salsum andT. bessarabicum from Crimea (documented on the basis of allozyme data elsewhere) is given a binomial,T. xmesohalobium Kirschner et?těpánek, nothosp. nov.