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1.
In the lichen genusUsnea different species ofTrebouxia-phycobionts as well as different haustorial types are known. The isolated and cultivated phycobiont ofUsnea longissima Ach. was studied by light- and electron microscopy and resembles in cytomorphological details the type ofTrebouxia impressa Ahmad. In addition to simple wall-to-wall contacts between the symbiotic components also intraparietal (=intrawall-)haustoria could be observed as the normal interaction type.
Frau Prof. Dr.Elisabeth Tschermak-Woess zu ihrem 70. Geburtstag gewidmet.  相似文献   

2.
Determination of the primary structure of the peptidoglycan of 15 strains of Oerskovia showed that three different peptidoglycan types occur. Oerskovia xanthineolytica strains contain the l-Lys-d-Ser--d-Asp type, whereas Oerskovia turbata strains show the new peptidoglycan types l-Lys-l-Thr--d-Asp or l-Lys-l-Thr--d-Glu, respectively. Research on the cytochromes of Oerskovia revealed the presence of a, b and c types. O. turbata can be clearly distinguished from O. xanthineolytica by the occurrence of cytochrome a 1 in cells, isolated from the stationary phase. The following conclusions were made: O. turbata and O. xanthineolytica can be clearly separated on the basis of different peptidoglycan types and cytochrome patterns. This distinction is in perfect correlation with the classical separation method of O. turbata and O. xanthineolytica on the basis of xanthine degradation. l-Lys-d-Ser--d-Asp peptidoglycan type does not only occur in O. xanthineolytica but also in some coryneform bacteria such as Corynebacterium manihot (Fiedler et al. 1970), Cellulomonas cartae (Stackebrandt et al. 1978; Stackebrandt and Kandler 1980), Brevibacterium fermentans and Nocardia cellulans.This paper is respectively dedicated to Professor Dr. O. Kandler, on the occasion of his 60th birthday  相似文献   

3.
Zusammenfassung In einem Konzentrationsbereich von 0,02–0,2 M hemmt d-Serin das Wachstum aller untersuchten Bakterien. Gleichzeitig traten morphologische Veränderungen der Bakterienzellen auf. In den nucleotidaktivierten Vorstufen von gehemmten Zellen wurden die d-Alaninreste des Peptidanteils ganz oder teilweise durch d-Serin ersetzt. Auch das Peptidoglycan enthielt d-Serin anstelle von d-Alanin, jedoch weiniger als in den Vorstufen. Zusätzlich war das modifizierte Peptidoglycan zu einem geringeren Anteil quervernetzt als das normale. Vier weitere d-Aminosäuren (Threonin, Valin, Leucin, Methionin) verursachten bei einer Konzentration von 0.2 M ähnliche Wirkungen wie d-Serin. Die Wirkungsweise von d-Aminosäuren auf die Peptidoglycansynthese kann daher allgemein wie folgt beschreiben werden: In Gegenwart von wachstumshemmenden Konzentrationen an d-Aminosäuren werden modifizierte nucleotidaktivierte Peptidoglycanvorstufen synthetisiert, die zu einem geringeren Ausmaß in das Peptidoglycan eingebaut und im Peptidoglycan schlechter quervernetzt werden. Der Ersatz von d-Alanin in Position 4 der Peptiduntereinheit ist dabei in der Regel am wirkungsvollsten. Nur bei Corynebacterium insidiosum und Staphylococcus aureus erwies sich der Ersatz in Position 5 als stärker hemmend. Diese Wirkungsweise entspricht weitgehend derjenigen von Glycin. Im Unterschied zur Wirkung von Glycin kann l-Alanin in Position 1 der Peptiduntereinheit nicht durch d-Aminosäuren ersetzt werden.
Mode of action of d-amino acids on the biosynthesis of peptidoglycan
The mechanism of growth inhibition by d-amino acids was studied. d-Serine at concentrations from 0.02–0.2 M was sufficient to cause partial growth inhibition in seven species of bacteria representing the four most common types of peptidoglycan. The inhibited cells displayed morphological alterations. In the nucleotide-activated peptidoglycan precursors of these cells, d-alanine residues in position 4 and/or 5 of the peptide moiety were partially or even completely replaced by d-serine. The peptidoglycan also contained d-serine instead of d-alanine, but the percentual content of d-serine was significantly lower than that in the precursors. In addition, the modified peptidoglycan was less cross-linked than the normal one. Four other d-amino acids (d-threonine, d-valine, d-leucine, d-methionine) at concentrations of about 0.2 M caused similar effects as did d-serine when applied to Corynebacterium callunae and Bacillus subtilis. Thus the mode of action of d-amino acids on peptidoglycan synthesis can be generally described as follows: in their presence, at growth inhibiting concentrations modified nucleotide-activated peptidoglycan precursors are formed in which d-alanine residues are replaced by the d-amino acids. They are less efficiently incorporated into peptidoglycan. A high percentage of the modified muropeptides remains non-cross-linked, since they are poor substrates for the transpeptidation reaction. In the majority of the organisms, cross-linking was decreased when d-alanine in position 4 of the peptide subunit was replaced, in two organisms (Corynebacterium insidiosum and Staphylococcus aureus) replacement in position 5 was most effective, however. The low extent of crosslinkage is consistent with the morphological aberrations of inhibited cells. In previous studies with glycine, results were described that were in close analogy to those obtained with d-amino acids. However, glycine can replace not only d-alanine residues in position 4 and 5 but also l-alanine in position 1 of the peptide subunit.

Verwendete Abkürzungen Dab Diaminobuttersäure - m-Dmp meso-Diaminopimelinsäure - GlcNAc oder G N-Acetylglucosamin - MurNAc oder M N-Acetylmuraminsäure  相似文献   

4.
TheSimaroubaceae generally have no true stipules. The stipule-like appendages of some genera proved to be pseudo- or metastipules (Weberling & Leenhouts 1965). There seem to be some exceptions, however: the generaCadellia (incl.Guilfoylia) andRecchia on the one hand, and theIrvingioideae on the other. As these taxa, with exception ofRecchia, have simple leaves, there are no indications that their stipule-like appendages might be pseudo- or metastipules. In regard to their position and ontogeny these appendages behave completely like true stipules. Assuming the view ofForman, one could conceive a morphological line from the long, broadly inserted axillary stipules of mostIrvingioideae to the small scaly triangular stipules ofIxonanthoideae. The similarities between the stipules ofIrvingioideae andErythroxylaceae (already emphasized byHallier and others), become even more evident when their ontogeny is investigated. TheIrvingioideae, therefore, might be regarded as a separate family (perhaps with some relation to theErythroxylaceae,Hallier) or as a subfamily ofIxonanthaceae (Forman).—In addition to data on stipules some results on the palynology and shoot anatomy of the generaCadellia (incl.Guilfoylia) andRecchia are reported. Their relationship with theSimaroubaceae also appears doubtful. If they are to be included, they represent a somewhat isolated group near the base of the family which otherwise has lost its stipules.
Herrn Univ.-Prof. Dr.Walter Leinfellner zum 70. Geburtstag gewidmet.  相似文献   

5.
The occurrence of cellobiose cleavage by phosphorolysis and by hydrolysis was investigated in Cellulomonas spec., C. uda, C. flavigena, and C. cartalyticum. Cellobiose phosphorylase (EC 2.4.1.20) was shown to be produced by Cellulomonas spec. when cellobiose or cellulose was used as sole source of energy and carbon but not with glycerol or glucose. Using inhibitors of protein synthesis as well as double labelling techniques it was shown that cellobiose phosphorylase is synthesized de novo in Cellulomonas spec. Aryl--D-glucosidase which was shown to be present in crude extracts of this microorganism as well is not involved in cellobiose cleavage.Abbreviations oNPGluc ortho-nitrophenyl--D-glucopyranoside - oNPGlucase ortho-nitrophenyl--D-glucopyranoside hydrolase (aryl--D-glucosidase) - CMC carboxymethyl-cellulose - CMCase carboxymethyl-cellulase - PAGE polyacrylamde disc gel electrophoresis Parts of this work were presented on the Herbsttagung der Gesellschaft für Biologische Chemie (Schimz et al. 1979) and on the 14th FEBS Meeting (Schimz et al. 1981)  相似文献   

6.
Viscin threads and other pollen connecting threads of some angiosperm families were investigated, especially those ofEricaceae. According to the definition adopted, viscin threads are ± long exinous processes which consist of exinous material and connect pollen grains or tetrads. Such viscin threads are found within theOnagraceae, Caesalpiniaceae, Ericaceae, andMimosaceae only. While they differ in structure and composition, they always consist of sporopollenin and exhibit a very strong stickiness, even after all viscid substances have been removed by acetolysis. In contrast, the pollen connecting scleroprotein threads ofOrchidaceae and the cellular threads ofStrelitzia reginae Aiton. (Musaceae) are not connected with the exine surface, are destroyed by acetolysis, and thus do not correspond to viscin threads.
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7.
Within agaric fungi whorled (multiple) clamps have been described so far only for the homothallicCoprinus myceliocephalus Lange. The new speciesCoprinus verticillatus Schulz-Weddigen (ined.) develops fertile mycelia which form septae without or with 1–5 clamps. Stronger hyphae tend to branch dichotomously. Most cells of the vegetative system contain many nuclei. Though single spore cultures remain sterile, they can develop multiple clamps, too. Moreover, very young mycelia produce a special type of oidiophores. According to its mating interactions a bipolar pattern characterizes the heterothallicC. verticillatus.
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8.
Bacillus subtilis has various cell wall hydrolases, however, the functions and hydrolase activities of some enzymes are still unknown. B. subtilis CwlK (YcdD) exhibits high sequence similarity with the peptidoglycan hydrolytic l,d-endopeptidase (PLY500) of Listeria monocytogenes phage and CwlK has the VanY motif which is a d-alanyl-d-alanine carboxypeptidase (Pfam: http://www.sanger.ac.uk/Software/Pfam/). The β-galactosidase activity observed on cwlK-lacZ fusion indicated that the cwlK gene was expressed during the vegetative growth phase, and Western blotting suggested that CwlK seems to be localized in the membrane. Truncated CwlK fused with a histidine-tag (h-ΔCwlK) was produced in Escherichia coli and purified on a nickel column. The h-ΔCwlK protein hydrolyzed the peptidoglycan of B. subtilis, and the optimal pH, temperature and NaCl concentration for h-ΔCwlK were pH 6.5, 37°C, and 0 M, respectively. Interestingly, h-ΔCwlK could hydrolyze the linkage of l-alanine-d-glutamic acid in the stem of the peptidoglycan, however, this enzyme could not hydrolyze the linkage of d-alanine-d-alanine, suggesting that CwlK is an l,d-endopeptidase not a d,d-carboxypeptidase. CwlK could not hydrolyze polyglutamate from B. natto or peptidoglycan of Staphylococcus aureus. This is the first report describing the characterization of an l,d-endopeptidase in B. subtilis and also the first report in bacteria of the characterization of a PLY500 family protein encoded in chromosomal DNA. Tatsuya Fukushima and Yang Yao contributed equally to this work.  相似文献   

9.
Population variability ofOphrys holosericea (Burm. f.)Greut. subsp.holosericea (=O. fuciflora Crantz subsp.fuciflora) from near Vienna (Austria), and of subsp.maxima (Fleischm.)Greut. andO. cornuta Steven with intermediates from the Dalmatian island Hvar (Yugoslavia) was analysed and illustrated by scatter diagrams. A hybrid origin of these intermediates is suggested. Aspects of hybridization betweenO. holosericea agg. andO. scolopax agg. are discussed.
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10.
In 83 species of the familiesMonotropaceae, Apocynaceae, Oleaceae, Scrophulariaceae, Lentibulariaceae, Bignoniaceae, Martyniaceae, Myoporaceae, Verbenaceae, Lamiaceae, Campanulaceae, andLiliaceae, protein bodies in the cell nuclei have been found, in 68 of these species for the first time. On the basis of their structure in accordance with morphological characters the generaBurgsdorfia, Hesiodia, Olisia, andPhlomoides of theLamiaceae are accepted;Lamium is divided intoLamium, Lamiastrum andOrvala; two new combinations are established:Kickxia campyloceras (Rech. fil. &Esfandiari)Speta andEtornotus papilionaceus (Burm. in L.)Speta. Deviating shape or lack of protein bodies corroborate former taxonomic decisions, e.g. the transfer ofMonotropa toMonotropaceae or the separation ofGaleopsis andLadanum; Veronica schmidtiana should not be included inPseudolysimachion. Systematic affinities are discussed primarily withinScrophulariaceae because nuclear protein bodies have been studied already in many species of this family. ForCampanula patula two 2 x populations are reported.
Herrn Professor Dr. L.Geitler zum 80. Geburtstag gewidmet.  相似文献   

11.
Saponaria stenopetala sp.n. in Eastern Afghanistan is close toS. pachyphylla Rech. f. andS. subrosularis Rech. f.—The nearest allies ofS. makranica sp.n. from Western Pakistan and Southeastern Iran areS. kermanensis Bornm. andS. floribunda (Kar. & Kir.)Boiss.
Flora Iranicae praecursores 36–37. — Praecursores praecurrentes in Pl. Syst. Evol.139, 313–317 (1982).  相似文献   

12.
The anaerobic fungus Piromyces sp. strain E2 metabolizes xylose via xylose isomerase and d-xylulokinase as was shown by enzymatic and molecular analyses. This resembles the situation in bacteria. The clones encoding the two enzymes were obtained from a cDNA library. The xylose isomerase gene sequence is the first gene of this type reported for a fungus. Northern blot analysis revealed a correlation between mRNA and enzyme activity levels on different growth substrates. Furthermore, the molecular mass calculated from the gene sequence was confirmed by gel permeation chromatography of crude extracts followed by activity measurements. Deduced amino acid sequences of both genes were used for phylogenetic analysis. The xylose isomerases can be divided into two distinct clusters. The Piromyces sp. strain E2 enzyme falls into the cluster comprising plant enzymes and enzymes from bacteria with a low G+C content in their DNA. The d-xylulokinase of Piromyces sp. strain E2 clusters with the bacterial d-xylulokinases. The xylose isomerase gene was expressed in the yeast Saccharomyces cerevisiae, resulting in a low activity (25±13 nmol min–1mg protein-1). These two fungal genes may be applicable to metabolic engineering of Saccharomyces cerevisiae for the alcoholic fermentation of hemicellulosic materials.  相似文献   

13.
Mycelial growth of an isolate ofT. bakamatsutake was tested in media with C/N ratio ranging from 0 to 50 and with 32 carbon and 12 nitrogen sources. The isolate grew best at the C/N ratio of 30. It utilized the monosaccharidesd-glucose,d-mannose, andd-fructose, the disaccharide trehalose, and polysaccharide pectin among the carbon sources; and yeast extract,l-glutamic acid, and ammonium compounds among the nitrogen sources. The growth of ten isolates and secretion of gluconic and oxalic acids were compared ind-glucose, trehalose, and pectin media. The utilization ofd-glucose, trehalose, and pectin differed among the ten isolates, but all the isolates secreted gluconic acid in thed-glucose media and oxalic acid in the pectin media.  相似文献   

14.
Radiant umbels result from the enlargement of peripheral phyllomes. We find the following patterns: 1) TheOrlaya-type: only one petal in the flower is enlarged. 2) TheCoriandrum-type: one whole and two half petals in the flower are enlarged. 3) TheArtedia-type: two half petals in the flower are enlarged. 4) TheXanthosia-type: the enlargement affects three involucellar bracts of which two become asymmetrical.—The enlargement of the phyllomes can effect the umbellet or the umbel or both. Obviously, this is the reason why many of these inflorescence systems display insufficient degrees of synorganization, with an optimum reached inArtedia and some species ofXanthosia.
Herrn Univ.-Prof. Dr.Walter Leinfellner zum 70. Geburtstag gewidmet.  相似文献   

15.
Zusammenfassung Die Polyalkohole Sorbitol, d-Mannitol, Ribitol, Xylitol, d-Arabitol, l-Arabitol und Erythritol werden von der obligat aeroben Hefe Rhodotorula gracilis über einen beweglichen Träger in der Zellmembran aufgenommen. Der Transportmechanismus ist aktiv, das erreichte Akkumulationsverhältnis ist jedoch bei allen Polyalkoholen erheblich geringer als bei Monosacchariden. Es nimmt, wie auch bei Monosacchariden, mit steigender Außenkonzentration ab, sogar auf Werte kleiner als 1.Kinetische Daten weisen darauf hin, daß das Trägersystem für Polyalkohole identisch ist mit dem für Monosaccharide, jedoch für Polyalkohole eine wesentlich geringere Affinität und maximale Geschwindigkeit aufweist. Aufgrund des hohen Affinitätsunterschiedes wird die Polyalkoholaufnahme in der Anwesenheit von Monosacchariden unterbunden.Die aufgenommenen Polyalkohole werden im Zellinneren nicht umgesetzt; eine Ausnahme stellen Ribitol und l-Arabitol dar, in deren Anwesenheit ein Abbausystem für Pentitole induziert wird.
Transport and utilization of alditols in the yeast Rhodotorula gracilis (glutinis) I. Constitutive transport of alditols
The obligate aerobic yeast Rhodotorula gracilis was found to take up the alditols d-glucitol, d-mannitol, ribitol, xylitol, d-arabinitol, l-arabinitol and erythritol by means of a constitutive mobile membrane carrier. This uptake involved active transport, that is, it was dependent on the supply of metabolic energy, leading to the accumulation of alditols inside the cells. The accumulation ratio (intracellular concentration to extracellular concentration, S i /S o ) was much lower for alditols than for monosaccharides. As for monosaccharides, this ratio decreased with increasing extracellular concentration, even to values below 1.The kinetic data showed that the carrier system for alditols was identical to that for monosaccharides, though it had a much lower affinity and maximum velocity for alditols. Hence the uptake of alditols was blocked in the presence of monosaccharides.Only ribitol and l-arabinitol were catabolized following enzyme induction. The other alditols were not broken down.
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16.
The following new hybrids are described:Euphrasia ×dilata = E. hirtella Jordan exReuter ×alpina Lam.;Euphrasia ×trikoviana = E. tricuspidata L. ×rostkoviana Hayne. The chromosome number ofEuphrasia tricuspidata L. has been established for the first time: 2n = 22.
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17.
Summary All fourCandida blankii isolates evaluated for growth in simulated bagasse hemicellulose hydrolysate utilized the sugars and acetic acid completely. The utilization ofd-xylose,l-arabinose and acetic acid were delayed by the presence ofd-glucose, but after glucose depletion the other carbon sources were utilized simultaneously. The maximum specific growth rate of 0.36 h–1 and cell yield of 0.47 g cells/g carbon source assimilate compared with published results obtained withC. utilis. C. blankii appeared superior toC. utilis for biomass production from hemicellulose hydrolysate in that it utilizedl-arabinose and was capable of growth at higher temperatures.  相似文献   

18.
Morphological and cytological investigations as well as crossing experiments were carried out withRanunculus seguieri Vill. and 4 species of theRanunculus alpestris L. group (R. alpestris L.,R. traunfellneri Hoppe,R. bilobus Bertol.,R. crenatus Waldst. & Kit.). ForR. seguieri andR. alpestris, localities and distribution are given in addition to extensive diagnoses. A key to the species includes morphological characteristics and distribution data forR. traunfellneri, R. bilobus, andR. crenatus. New diagnostic characters are described. Crossing experiments betweenR. seguieri and the species of theR. alpestris group were unsuccessful. All 5 species have a chromosome number of 2n = 16, the record forR. bilobus is new. There is no statistically significant difference between the karyotypes ofR. seguieri andR. alpestris s. str. Nevertheless, according to morphological evidence and crossing experiments,R. seguieri is not closely related to theR. alpestris group.
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19.
The pseudanthia ofHeliopsis scabra andRudbeckia vulgaris (Asteraceae) were examined during the anthesis for differences in their UV patterns. Distinct changes in the reflectance and absorbance properties could be observed. The results suggest a close correlation between different stages of floral development and pollinator attraction.
Herrn Prof. Dr.Lothar Geitler zum 90. Geburtstag gewidmet.  相似文献   

20.
Topotype specimens of the Middle OrdovicianHyolithes acutus Eichwald, 1840, which is the type of the genus that lent its name to a family, order, class, and even phylum according to some, andH. latus Eichwald, 1860 allow that genus and those species to be firmly established on a sound, morphologic basis. In addition, preservation of the types ofHyolithes striatus Eichwald, 1860 is sufficiently good to warrant reassignment toDorsolinevitus Syssoiev, 1958. In contrast, the type ofH. insularis Eichwald, 1860 is incompletely preserved, and this species is not recognizable beyond the type material. The concept of the family Hyolithidae is revised to more closely conform to the morphology ofHyolithes, with authorship herein ascribed toSyssoiev (1958) rather than toNicholson (1872). The stratigraphic distribution of these taxa suggests thatHyolithes as defined herein first appears in the Middle Ordovician, but extends into at least the Lower Devonian, as suggested by two species from the Barrandian region of the Czech Republic. Their geographic distribution further re-enforces the notion of two distinct paleobiogeographic provinces based on hyoliths, a Mediterranean province and Baltic province, with almost no mixing of hyolith faunas during the Ordovician.   相似文献   

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