Biologie - Open Access LMU - Teil 02/02

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Supplementary material to this book contains the following Adobe-Writer (.pdf) files: an overview of the material, the color coding for the map on the title page), and supporting information for chapter 1, 14, 20, 22 and 30. Some of the files contain further links to materials on this server, in particular is there a collection of structural formulas accessible from the material to chapter 1. Please, click on the respective files for downloading. Any reference should cite the full title of the book.

Sun, 1 Jan 1995 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3195/ http://epub.ub.uni-muenchen.de/3195/1/3195.pdf Radtke-Schuller, Susanne; Schuller, Gerd Radtke-Schuller, Susanne und Schuller, Gerd (1995): Auditory cortex of the rufous horseshoe bat. 1. Physiological response properties to acoustic stimuli and vocalizations and the topographical distribution of neurons. In: European Journal of Neuroscience, Vol. 7: pp. 570-591. Biologie

Sun, 1 Jan 1995 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3197/ http://epub.ub.uni-muenchen.de/3197/1/032.pdf Kleiser, A.; Schuller, Gerd Kleiser, A. und Schuller, Gerd (1995): Responses of Collicular Neurons to Acoustic Motion in the Horseshoe Bat Rhinolophus rouxi. In: Naturwissenschaften, Vol. 82, Nr. 7: pp. 337-340.

Sun, 1 Jan 1995 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3583/ http://epub.ub.uni-muenchen.de/3583/1/3583.pdf Soll, Jürgen; Seedorf, M. Mathis, Paul (Hrsg.) (1995): The protein import machinery of chloroplasts. International Congress on Photosynthesis , 20 - 25 August 1995, Montpellier. Biologie

Polarization pump-probe femtosecond spectroscopy was used to investigate photoinduced optical density changes in allophycocyanin (APC) trimers at 635–690 nm after excitation with 230-fs pulses at 618 nm. The initial bleaching observed at λ < 645 nm is followed by subpicosecond absorption recovery corresponding to 430 ± 40 fs recovery kinetics measured at 615 nm with 70-fs pulses. Only the red part of the APC absorption band remains strongly bleached at 3 ps after excitation. The spectral and kinetic results can be described in terms of two different models of interaction between neighbouring α-80 and β-81 chromophores of APC trimers. According to the first one, the observed subpicosecond kinetics corresponds to relaxation between the levels of excitonically coupled, spectrally identical α-80 and β-81 chromophores. Excited state absorption to doubly excited excitonic state should in this case contribute to the measured difference spectra. According to the second one, the femtosecond excitation energy transfer in APC trimers takes place between a donor chromophore absorbing predominantly at 620 nm and an acceptor chromophore absorbing at 650 nm. The high anisotropy value observed at 615 nm during the first 1.2 ps is in good agreement with the donor-acceptor model. Anisotropy values calculated in the 635–675 nm spectral region at 3 ps after excitation are in the 0.1–0.25 range corresponding to an angle of 30°–45° between donor and acceptor transition dipole orientations. The high anisotropy obtained at 658 nm during the excitation is probably due to stimulated emission of the donor chromophore.

Soret resonance and Qy preresonance Raman spectra are reported and compared for a series of (bacterio)chlorophylls. Chlorophyll a, 2-acetylchlorophyll a, bacteriochlorophyll a and 2-vinylbacteriochlorophyll a were studied in the non-protic solvent tetrahydrofuran. These experiments were designed to identify Raman bands corresponding to the stretching mode(s) of the vinyl group at the C-2 position of ring I of chlorophyll a and 2-vinylbacteriochlorophyll a, and to ascertain whether additional bands corresponding to Ca Cm and/or Cb Cb vibrations could be observed in the 1615-1660 cm-1 region. Raman spectra of chlorophyll a and 2-vinylbacteriochlorophyll a exhibit a 1625 cm-1 band, which is absent from the Raman spectra of 2-acetylchlorophyll a and bacteriochlorophyll a. It is assigned to the vC2a C2b mode of the vinyl group. No other band can be definitively assigned to any mode predominantly arising from vinyl motions. The acetyl-containing molecules 2-acetylchlorophyll a and bacteriochlorophyll a give rise to a ca. 1070 cm-1 band, which appears to be related to the presence of the acetyl substituent. The 1615-1660 cm-1 region of the Raman spectra of all four derivatives did not contain any additional band which could be ascribed to modes involving the vCa Cm and/or Cb Cb coordinates.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2451/ http://epub.ub.uni-muenchen.de/2451/1/2451.pdf Gottschalk, Lothar; Lottspeich, Fritz; Scheer, Hugo Gottschalk, Lothar; Lottspeich, Fritz und Scheer, Hugo (1994): Reconstitution of an allophycocyanin trimer complex containing the C-terminal 21-23 kDa domain of the core-membrane linker polypeptide Lcm. In: Zeitschrift für Naturforschung C: Journal of Biosciences, Vol

Zero field absorption detected magnetic resonance hole burning measurements were performed on photosynthetic reaction centers of the bacteria Rhodobacter sphaeroides R26 and Rhodopseudomonas viridis. Extrapolation to zero microwave power yielded pseudohomogeneous linewidths of 2.0 MHz for Rhodopseudomonas viridis, 1.0 and 0.9 MHz for the protonated forms of Rhodobacter sphaeroides R26 with and without monomer bacteriochlorophyll exchanged, and 0.25 MHz as an upper limit for fully deuterated reaction centers of Rhodobacter sphaeroides R26. The measured linewidths were interpreted as being due to unresolved hyperfine interaction between the nuclear spins and the triplet electron spin, the line shape being determined by spectral diffusion among the nuclei. The difference in linewidths between Rhodobacter sphaeroides R26 and Rhodopseudomonas viridis is then explained by triplet delocalization on the special pair in the former, and localization on one dimer half on the latter. In the fully deuterated sample, four quadrupole satellites were observed in the hole spectra arising from the eight 14N nitrogens in the special pair. The quadrupole parameters seem to be very similar for all nitrogens and were determined to =1.25±0.1 MHz and =0.9±0.1 MHz. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

A series of substituted bacteriochlorophyll molecules, all used in reconstitution experiments of reaction centers of Rhodobacter sphaeroides (Struck et al. Biochim. Biophys. Acta 1991, 1060, 262-270), were characterized by EPR, electron-nuclear double (ENDOR), and electron-nuclear-nuclear triple (TRIPLE) resonance spectroscopy in their monomeric radical cation states. Effects of different substituents at position 3 in the porphyrin macrocycle were considered, especially for two «crosslinks» between plant and bacterial chlorophylls. These are 3-vinylbacteriochlorophyll where the «bacteria» acetyl group at position 3 was substituted by vinyl and 3-acetylchlorophyll where the «plant» vinyl group was substituted by acetyl

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2472/ http://epub.ub.uni-muenchen.de/2472/1/2472.pdf Leupold, D.; Neef, E.; Voigt, B.; Nowak, F.; Ehlert, J.; Hirsch, J.; Bandilla, M.; Scheer, Hugo Leupold, D.; Neef, E.; Voigt, B.; Nowak, F.; Ehlert, J.; Hirsch, J.; Bandilla, M. und Scheer, Hugo (1994): Substructure analysis of the bacterial antenna LH II by nonlinear polarization spectroscopy in the frequency domain. In: Lietuvos fizikos žurnalas, Vol. 34: pp. 339-343.

15N-substituted bacteriochlorophyll a (BChl a) was extracted from the cells of Rhodobacter sphaeroides 2.4.1 grown in a medium containing 15N-ammonium sulfate and yeast concentrate. The T1 Raman spectra of 14N-and 15N-BChl a were obtained as the difference spectra of high-power minus low-power of one-color, pump-and-probe measurements using 420 nm, 5 ns pulses. A set of empirical assignments of the T1 Raman lines was made, based on shifts upon 14N→15N substitution. The S0 Raman spectra of the two BChls were also obtained by using the 457.9 nm cw beam, and a set of assignments of the S0 Raman lines was given for comparison.

The mechanism of formation of the formyl group of chlorophyll b has long been obscure but, in this paper, the origin of the 7-formyl-group oxygen of chlorophyll b in higher plants was determined by greening etiolated maize leaves, excised from dark-grown plants, by illumination under white light in the presence of either H218O or 18O2 and examining the newly synthesized chlorophylls by mass spectroscopy. To minimize the possible loss of 18O label from the 7-formyl substituent by reversible formation of chlorophyll b-71-gem-diol (hydrate) with unlabelled water in the cell, the formyl group was reduced to a hydroxymethyl group during extraction with methanol containing NaBH4: chlorophyll a remained unchanged during this rapid reductive extraction process. Mass spectra of chlorophyll a and [7-hydroxymethyl]-chlorophyll b extracted from leaves greened in the presence of either H218O or 18O2 revealed that 18O was incorporated only from molecular oxygen but into both chlorophylls: the mass spectra were consistent with molecular oxygen providing an oxygen atom not only for incorporation into the 7-formyl group of chlorophyll b but also for the well-documented incorporation into the 131-oxo group of both chlorophylls a and b [see Walker, C. J., Mansfield, K. E., Smith, K. M. & Castelfranco, P. A. (1989) Biochem. J. 257, 599–602]. The incorporation of isotope led to as much as 77% enrichment of the 131-oxo group of chlorophyll a: assuming identical incorporation into the 131 oxygen of chlorophyll b, then enrichment of the 7-formyl oxygen was as much as 93%. Isotope dilution by re-incorporation of photosynthetically produced oxygen from unlabelled water was negligible as shown by a greening experiment in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The high enrichment using 18O2, and the absence of labelling by H218O, unequivocally demonstrates that molecular oxygen is the sole precursor of the 7-formyl oxygen of chlorophyll b in higher plants and strongly suggests a single pathway for the formation of the chlorophyll b formyl group involving the participation of an oxygenase-type enzyme.

The modification of reaction centers from Rhodobacter sphaeroides by the introduction of pheophytins instead of bacteriopheophytins leads to interesting changes in the primary photosynthetic reaction: long-living populations of the excited electronic state of the special pair P* and the bacteriochlorophyll anion B−A show up. The data allow the determination of the energetics in the reaction center. The free energy of the first intermediate P+B−A, where the electron has reached the accessory bacteriochlorophyll BA lies ≈ 450 cm−1 below the initially excited special pair P*.

Three building blocks of the antenna complexes of the cyanobacterium Westiellopsis prolifica were studied: PEC(X), which is similar to the α-subunit of phycoerythrocyanin (PEC), trimers of PEC and monomers derived from these by deaggregation with KSCN. The fit of the fluorescence decay curve of PEC(X) requires at least four exponentials, although it supposedly contains only one chromophore. The coherent anti-Stokes Raman scattering (CARS) spectra indicate that the heterogeneity observed is due to geometrical isomers, which are in part generated by photoinduced processes. A similar heterogeneity in chromophore structure and properties is also found in the monomers, where four exponentials are needed to fit the fluorescence decay curve. As in trimers, there is a long-lived, low-amplitude component, which can be assigned to impurities and/or oxidation products. The energy transfer time between the two phyocyanobilin chromophores in the β-subunit is about 500 ps; the lifetime of the fluorescing β-chromophore is 1.5 ns. The phycoviolobilin chromophore in the α-subunit adopts different geometries characterized by fluorescence lifetimes of about 240 and 800 ps. No evidence was found for energy transfer between the α-chromophore and the β-chromophores. This energy transfer occurs in trimers on a time scale of less than 20 ps; the energy transfer time between the two different types of β-chromophore is about 250 ps and the lifetime of the terminal emitter is about 1.5 ns. The excited state kinetics are therefore similar to those of PEC trimers from Mastigocladus laminosus, as are the CARS spectra, indicating a similar chromophore—protein arrangement. In comparison with phycocyanin, the ordering of the excited states of chromophores β84 and β155 may be changed. Although PEC trimers of Westiellopsis prolifica show almost as good a photostability as trimers of Mastigocladus laminosus, monomers are so photolabile that no CARS spectra could be recorded.

By means of fluorescence spectroscopy and nonlinear absorption experiments, excited-state processes of the modified pigments [3-acetyl]-chlorophyll a, [31-OH]-bacteriochlorophyll a and [3-vinyl]-bacteriochlorophyll a were investigated and compared with those of chlorophyll a and bacteriochlorophyll a.

A gene (X33) localized on human chromosome 1 has been detected by crossreaction of its fusion protein with a monospecific antiserum directed against human vitamin-D-binding protein (hDBP; group-specific component). Its cDNA sequence analysis showed no evident homologies neither to the sequence encoding hDBP nor to any other sequence. The largest cDNA clone of 3.2 kb includes a 897-bp coding region and a large 3’ untranslated region with at least four polyadenylation sites. Further cDNA amplification using PCR demonstrated a total cDNA length of approx. 3.7 kb. Northern blot analysis revealed signals at about 2.2-2.5 kb and 4.0 kb, the shorter transcripts representing mRNAs using one of the two polyadenylation sites at about 2.0 kb. Synthesis of the 299-amino-acid polypeptide (33 kDa) in the bacterial host, with subsequent Western blot analysis, verified the sequence-specific recognition by the hDBPspecific antiserum. The search of protein databanks revealed no homology of HK33 to any known sequence. Since the gene is transcribed in all cells and tissues tested so far, it is a strong candidate for another housekeeping gene.

A purification process for the monclonal anti-CD4 antibody MAX.16H5 was developed on an analytical scale using (NH&SO, precipitation, anion-exchange chromatography on MonoQ or Q-Sepharose, hydrophobic interaction chromatography on phenyl- Sepharose and gel filtration chromatography on Superdex 200. The purification schedule was scaled up and gram amounts of MAX.16H5 were produced on corresponding BioPilot columns. Studies of the identity, purity and possible contamination by a broad range of methods showed that the product was highly purified and free from contaminants such as mouse DNA, viruses, pyrogens and irritants. Overall, the analytical data confirm that the monoclonal antibody MAX.16H5 prepared by this protocol is suitable for human therapy.

An expressed beta-tubulin gene (TUBB) has previously been localized to chromosome region 6pter-p21 in man. By using a panel of deletion mutant cell lines and radiation-reduced hybrids containing fragments of chromosome 6, the TUBB locus could be mapped to the HLA class I region at 6p21.3. A long range restriction map including TUBB and several HLA class I genes was then generated by rotating field gel electrophoresis. The results show that TUBB maps to a segment 170-370 kb telomeric of HLA-C. This location suggests that a mutation at the TUBB locus could be the cause for certain forms of HLAlinked microtubule dysfunction, including immotile cilia syndrome.

Classical, polymorphic major histocompatibility complex class I molecules are expressed on most nucleated cells.They present peptides at the cell surface and, thus, enable the immune system to scan peptides for their antigenicity. The function of the other, nonclassical class I molecules in man is controversial. HLA-G which has been shown by transfection experiments to be expressed at the cell surface, is only transcribed in placental tissue and in the fetal eye.Therefore, a role of HLA-G in the control of rejection of the allogeneic fetus has been discussed. We found that HLA-G expression is induced in keratinocytes by culture in vitro. Three different alternative splicing products of HLA-G can be detected: a full length transcript, an mRNA lacking exon 3 and a transcript devoid of exon 3 and 4. Reverse transcription followed by polymerase chain reaction also revealed the presence of HLA-G mRNA in vivo in biopsies of either diseased or healthy skin.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3143/ http://epub.ub.uni-muenchen.de/3143/1/3143.pdf Webster, John A.; Bannermann, Tammy L.; Hubner, Romeo J.; Ballard, Deborah N.; Cole, Eileen M.; Bruce, James L.; Fiedler, Franz; Schubert, Karin; Kloos, Wesley Webster, John A.; Bannermann, Tammy L.; Hubner, Romeo J.; Ballard, Deborah N.; Cole, Eileen M.; Bruce, James L.; Fiedler, Franz; Schubert, Karin und Kloos, Wesley (1994): Identification of the Staphylococcus sciuri Species Group with EcoRI Fragments Containing rRNA Sequences and Description of Staphylococcus vitulus sp. nov. In: International Journal of Systematic Bacteri

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3196/ http://epub.ub.uni-muenchen.de/3196/1/031.pdf Grothe, Benedikt; Schweizer, Hermann; Pollak, George D.; Schuller, Gerd; Rosemann, Christina Grothe, Benedikt; Schweizer, Hermann; Pollak, George D.; Schuller, Gerd und Rosemann, Christina (1994): Anatomy and Projection Patterns of the Superior Olivary Complex in the Mexican Free-Tailed Bat, Tadarida brasiliensis mexicana. In: Journal of Comparative Neurology, Vol. 343, Nr. 4: pp. 63

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3217/ http://epub.ub.uni-muenchen.de/3217/1/019.pdf Faust, Daniela M.; Boshart, Michael; Schütz, Günther; Weiss, Mary C. Faust, Daniela M.; Boshart, Michael; Schütz, Günther und Weiss, Mary C. (1994): Constancy of Expression of the Protein Kinase A Regulatory Subunit Rla in Hepatoma Cell Lines of Different Phenotypes. In: Cell Growth and Differentiation, Vol. 5: pp. 47-53.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3225/ http://epub.ub.uni-muenchen.de/3225/1/3225.pdf Grothe, Benedikt Grothe, Benedikt (1994): Interaction of excitation and inhibition in processing of pure tone and amplitude-modulated stimuli in the medial superior olive of the mustached bat. In: Journal of Neurophysiology,

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3226/ http://epub.ub.uni-muenchen.de/3226/1/002.pdf Grothe, Benedikt; Sanes, Dan H. Grothe, Benedikt und Sanes, Dan H. (1994): Synaptic Inhibition Influences the Temporal Coding Properties of Medial Superior Olivary Neurons. An in vitro Study. In: Journal of Neuroscience, Vol. 14, Nr. 3: pp. 1701-1709.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3227/ http://epub.ub.uni-muenchen.de/3227/1/003.pdf Grothe, Benedikt; Schweizer, Hermann; Pollak, George D.; Schuller, Gerd Grothe, Benedikt; Schweizer, Hermann; Pollak, George D. und Schuller, Gerd (1994): Anatomy and projection patterns of the superior olivary comlex in the mexican free-tailed bat, Tadarida brasiliensis mexicana. In: Journal of Comparative Neurology, Vol. 343, Nr. 4: pp. 630

Abstract A dense population of the purple sulfur bacterium Amoebobacter purpureus in the chemocline of meromictic Mahoney Lake (British Columbia, Canada) underwent consistent changes in biomass over a two year study period. The integrated amount of bacteriochlorophyll reached maxima in August and declined markedly during early fall. Bacteriochlorophyll was only weakly correlated with the light intensity and water temperature in the chemocline. In the summer, bacterial photosynthesis was limited by sulfide availability. During this period the intracellular sulfur concentration of A. purpureus cells decreased. A minimum concentration was measured at the top of the bacterial layer in August, when specific photosynthetic rates of A. purpureus indicated that only 14% of the cells were photosynthetically active. With the exception of a time period between August and September, the specific growth rates calculated from CO2 fixation rates of A. purpureus were similar to growth rates calculated from actual biomass changes in the bacterial layer. Between August and September 86% of the A. purpureus biomass disappeared from the chemocline and were deposited on the littoral sediment of Mahoney Lake or degraded within the mixolimnion. This rise of cells to the lake surface was not mediated by an increase in the specific gas vesicle content which remained constant between April and November. The upwelling phenomenon was related to the low sulfur content of A. purpureus cells and a low resistance of surface water layers against vertical mixing by wind.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3268/ http://epub.ub.uni-muenchen.de/3268/1/3268.pdf Kosch, Kerstin; Jacobi, Andreas; Parniske, Martin; Werner, Dietrich; Müller, Peter Kosch, Kerstin; Jacobi, Andreas; Parniske, Martin; Werner, Dietrich und Müller, Peter (1994): The impairment of the nodulation process, induced by a bradyrhizobium-japonicum exopolysaccharide mutant is determined by the genotype of the host-plant. In: Zeitschrift für Naturforschung C,

After a short summary on the ecology and rhizosphere biology of symbiotic bacteria and vesicular-arbuscular (VA) mycorrhiza fungi and their application as microbial inocula, results on competitiveness and communication are summarized. Stress factors such as high temperature, low soil pH, aluminium concentrations and phytoalexins produced by the host plants were studied withRhizobium leguminosarum bv.phaseoli andRhizobium tropici onPhaseolus beans. Quantitative data for competitiveness were obtained by usinggus + (glucoronidase) labelled strains, which produce blue-coloured nodules. ForPhaseolus-nodulating rhizobia, a group specific DNA probe was also developed, which did not hybridize with more than 20 other common soil and rhizosphere bacteria. Results from several laboratories contributing to knowledge of signal exchange and communication in theRhizobium/Bradyrhizobium legume system are summarized in a new scheme, including also defense reactions at the early stages of legume nodule initiation. Stimulating effects of flavonoids on germination and growth of VA mycorrhiza fungi were also found. A constitutive antifungal compound in pea roots, -isoxazolinonyl-alanine, was characterized.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3270/ http://epub.ub.uni-muenchen.de/3270/1/3270.pdf Parniske, Martin; Schmidt, Petra; Kosch, Kerstin; Müller, Peter Parniske, Martin; Schmidt, Petra; Kosch, Kerstin und Müller, Peter (1994): Plant defense responses of host plants with determinate nodules induced by eps-defective exob mutants of bradyrhizobium-japonicum. In: Molecular Plant-Microbe Interactions, Vol. 7, Nr. 5: pp.

A new comprehensive communication concept in the Rhizobium/Bradyrhizobium legume symbiosis was developed. It includes a root zone specific flavonoid exudation, the differential activity of phenylpropane/acetate pathway derivatives on chemotaxis, nod-gene inducing activity and phytoalexin resistance induction on the microsymbiont side (Bradyrhizobium). Nod factor production from the microsymbiont affects the host plant in root hair curling and meristem induction. Phytoalexin production in the host plant is also an early response, however repressed to a low level after a few hours. Another strategy of the microsymbiont to overcome phytoalexin effects is degradation of phytoalexins in Rhizobium leguminosarum bv. vicieae. Competitiveness within the same infection group of the microsymbiont was studied with gus-gene fusion, using the blue coloured nodules to easily discriminate marked strains from unmarked competitors. New exopolysaccharide (EPS) mutants of Bradyrhizobium japonicum were reconstructed homologous with a DNA region to exoB gene of Rhizobium meliloti. Their clearly reduced competitiveness of nodulation, demonstrates that exopolysaccharides of Bradyrhizohium japonicum also have an important function during the early stages of this symbiotic interaction.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3313/ http://epub.ub.uni-muenchen.de/3313/1/3313.pdf Wullimann, Mario F.; Roth, G. Wullimann, Mario F. und Roth, G. (1994): Descending telencephalic information reaches longitudinal torus and cerebellum via the dorsal preglomerular nucleus in the teleost fish, Pantodon buchholzi. A case of neural preaptation. In: Brain, Behavior a

As a molecular marker for head specification in Hydra, we have cloned an epithelial cell-specific gene which responds to early signals of head formation. The gene, designated ks1, encodes a 217-amino acid protein lacking significant sequence similarity to any known protein. KS1 contains a N-terminal signal sequence and is rich in charged residues which are clustered in several domains. ks1 is expressed in tentacle-specific epithelial cells (battery cells) as well as in a small fraction of ectodermal epithelial cells in the gastric region subjacent to the tentacles. Treatment with the protein kinase C activator 12-O-tetradecanoylphorbol-13- acetate (TPA) causes a rapid increase in the level of ks1 mRNA in head-specific epithelial cells and also induces ectopic ks1 expression in cells of the gastric region. Sequence elements in the 5 ¢-flanking region of ks1 that are related to TPA-responsive elements may mediate the TPA inducibility of ks1 expression. The pattern of expression of ks1 suggests that a ligand-activated diacylglycerol second messenger system is involved in head-specific differentiation.

A cDNA clone encoding a 253 amino acid tropomyosin was isolated from Hydra in a differential screen for headspecific genes. The Hydra tropomyosin gene, designated trop1, is a single copy gene, lacks introns and is strongly expressed in tentacle-specific epithelial cells. Analysis of protein synthesis in head and gastric tissue indicated a high rate of tropomyosin synthesis in head tissue. Immunolocalization of tropomyosin in tentacle tissue revealed a cushion-like tropomyosin-containing structure within battery cells at the base of nematocytes. The structure appears to form part of the cytoskeletal anchor for nematocytes. Tropomyosin cushions were also observed in epithelial cells along the body column, which contain mounted stenotele nematocytes.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3461/ http://epub.ub.uni-muenchen.de/3461/1/3461.pdf Alefsen, H.; Waegemann, Karin; Soll, Jürgen Alefsen, H.; Waegemann, Karin und Soll, Jürgen (1994): Analysis of the chloroplast protein import machinery. In: Journal of Plant Physiology, Vol. 144: pp. 339-345. Biologie

The chloroplast outer envelope protein OEP86 functions as a receptor in precursor protein translocation into chloroplasts. Sequence analysis suggests that the precursor of OEP86 is directed to the chloroplast outer envelope by a cleavable, negatively charged, and unusually long amino-terminal peptide. This presequence is unlike other potential targeting signals and suggests the existence of another membrane insertion pathway. Insertion of precursor OEP86 required the hydrolysis of adenosine triphosphate and the existence of surface exposed chloroplast membrane components, and it was not competed by another precursor protein destined for the internal plastid compartments.

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/5079/ http://epub.ub.uni-muenchen.de/5079/1/039.pdf Bosch, F. van den; Gabriel, Wilfried Bosch, F. van den und Gabriel, Wilfried (1994): A model of growth and development in copepods. In: Limnology and Oceanography, Vol. 39, Nr. 7: pp. 1528-1542. Biologie

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/5137/ http://epub.ub.uni-muenchen.de/5137/1/5137.pdf Gabriel, Wilfried; Bürger, Reinhard Gabriel, Wilfried und Bürger, Reinhard (1994): Extinction risk by mutational meltdown. Synergistic effects between population regulation and genetic drift. In: Loeschcke, Volker (Hrsg.), Conservation genetics. Birkhäuser: Basel [u.a.], pp. 69-84. Biologie

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/5138/ http://epub.ub.uni-muenchen.de/5138/1/041.pdf Matveev, Vladimir; Gabriel, Wilfried Matveev, Vladimir und Gabriel, Wilfried (1994): Competetive exclusion in Cladocera through elevated mortality of adults. In: Journal of Plankton Research, Vol. 16: pp. 1083-1094. Biologie

Sat, 1 Jan 1994 12:00:00 +0100 http://epub.ub.uni-muenchen.de/5139/ http://epub.ub.uni-muenchen.de/5139/1/5139.pdf Gabriel, Wilfried Gabriel, Wilfried (1994): "Mutational Meltdown": Aussterberisiko durch Anhäufung schädlicher Mutationen. In: Zeitschrift für Ökologie und Naturschutz, Vol. 3: pp. 161-165.

Nonlinear polarization spectroscopy in the frequency domain allows rate constant determinations of fast electronic energy and phase relaxations together with characterization of the type of line broadening. Application of this method to the B850 component of the isolated B800–850antenna ofRhodobacter sphaeroides at room temperature shows that B850 is inhomogeneously broadened, with homogeneous widths between 30 and 200 cm−1, depending on the spectral position of the subforms. The corresponding phase relaxation times are clearly in the subpicosecond range. There is also indication of an up-to-now unspecified1–5 ps energy relaxation channel per subunit.

Fri, 1 Jan 1993 12:00:00 +0100 http://epub.ub.uni-muenchen.de/2365/ http://epub.ub.uni-muenchen.de/2365/1/224.pdf Scheer, Hugo; Schneider, Siegfried Scheer, Hugo und Schneider, Siegfried (1993): Photosynthetic Antenna Systems: Introduction. In: Photochemistry and Photobiology, Vol. 57, Nr. 1: p. 1. Biologie

The photochemical activities of phycoerythrocyanin α-subunits from Mastigocladus laminosus separated by isoelectric focusing were tested by irradiating at 500, 550, 577 and 600 nm. Two types of photoreversible photochromic responses have been characterized by absorption and absorption difference spectroscopy. Type I is the well-known absorption shift from 571 to 506 nm. Type II is a new response characterized by a line-broadening of the 570 nm absorption.

Two phycoerythrocyanin (PEC) fractions have been obtained from the phycobilisomes of the cyanobac-terium Westiellopsis prolifica ARM 365. They have been characterized by absorption, fluorescence and circular dichroism spectroscopy. One of them is spectroscopically similar to a PEC trimer known from other organisms. Whereas efficient energy transfer from its violin (α-84) to the cyanin (β-84, 155) chromophores is efficient in the trimer (αβ it is impeded after dissociation to the monomer (α,β). A second fraction of PEC which we earlier termed PEC(X) (Maruthi Sai et al., Photochem. Photobiol. 55,119–124, 1992), exhibited the spectral properties similar to that of the α-subunit of PEC from Mastigocladus laminosus. With this highly photoactive fraction, the circular dichroism spectra of the violobilin chromophore in both photoreversible states were obtained.