@article{FrankeKartenbeckZentgrafetal.1971, author = {Franke, Werner W. and Kartenbeck, J{\"u}rgen and Zentgraf, Hanswalter and Scheer, Ulrich and Falk, Heinz}, title = {Membrane-to-membrane cross-bridges. A means to orientation and interaction of membrane faces}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32122}, year = {1971}, abstract = {No abstract available}, language = {en} } @article{FrankeKartenbeckKrienetal.1972, author = {Franke, Werner W. and Kartenbeck, J{\"u}rgen and Krien, S. and VanderWoude, W. J. and Scheer, Ulrich and Morr{\´e}, D. J.}, title = {Inter- and intracisternal elements of the Golgi apparatus: A system of membrane-to-membrane cross-links}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39514}, year = {1972}, abstract = {Electron opaque cross-bridge structures span the inter- and intracisternal spaces and provide membrane-to-membrane connections between adjacent cisternae of dictyosomes of pollen tubes of Clivia and Lilium. Additionally, the classic intercisternal rods, characteristic of intercisternal regions near the maturing face of dictyosomes, are connected with the adjacent membranes through similar cross-bridge elements. We suggest that these structural links are responsible for maintaining the flattened appearance of the central parts of Golgi apparatus cisternae as well as for the coherence of cisternae within the stack. Observations on other plant (e.g. microsporocytes of Canna) and animal cells (e.g. rodent liver and hepatoma cells, newt spermatocytes) show that such an array of membrane cross-links is a universal feature of Golgi apparatus architecture. The cross-bridges appear as part of the complex "zone of exclusion" which surrounds dictyosomes, entire Golgi apparatus and Golgi apparatus equivalents in a variety of cell types.}, language = {en} } @article{FrankeJaraschHerthetal.1975, author = {Franke, Werner W. and Jarasch, Ernst-Dieter and Herth, Werner and Scheer, Ulrich and Zerban, Heide}, title = {Cytology : general and molecular cytology}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41458}, year = {1975}, abstract = {The present review discusses some general aspects of membrane structure and problems of membrane isolation and membrane biochemistry, with particular focus on the endoplasmic reticulum.}, subject = {Botanik}, language = {en} } @article{FrankeBergerFalketal.1974, author = {Franke, Werner W. and Berger, S. and Falk, Heinz and Spring, H. and Scheer, Ulrich and Trendelenburg, Michael F. and Schweiger, H. G. and Herth, W.}, title = {Morphology of the nucleo-cytoplasmic interactions during the development of Acetabularia cells. I. The vegetative phase}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32363}, year = {1974}, abstract = {The ultrastructure of th e growin g and ma turing primary nucleus of Acetabularia medite rranea and Acetabularia major has been studied with the use of various fi xation procedures. Particular interest has been focused on the deta ils of the nuclear periphery and the perinuclear region. It is demonstrated that early in nuclear grow th a characteristic perinucl ear structura l complex is formed which is, among the eukaryotic cells, unique to Acetabularia and re lated genera. This perinuclear system consists essentially of a) the nuclear envelope with a very hi gh pore frequency and various pore complex assoc iat ion s w ith granular and/or threadlike structures some of which are continuous with the nucleolus; b) an approx imate ly 100 nm thick intermediate zone densely filled with a filam entOus material and occasional sma ll membraneous structures from which the typical cytOplasmic and nuclear organe lles and particles are excl ud ed ; c) an adjacent Iacunar labyrinthum which is interrupted by many plasmatic junction channels between the intermed iate zone and the free cytOplasm; d) numerous dense perinuclear bodies in the juxtanuclear cytOplasm which a re especia lly frequent at the junction channels and reveal a composition of aggregated fibrillar and granul ar structures; e) very dense exclusively fibrill ar agg regates which occur either in assoc iation with t he perinuclear region of the lacunar labyrinthum or, somewhat further out, in the cytOplasmic strands between the bra nches of the lacun ar labyrinthum in the form of slender, characteristic rods or "sausages".}, language = {en} } @phdthesis{Franke2019, author = {Franke, Christian}, title = {Advancing Single-Molecule Localization Microscopy: Quantitative Analyses and Photometric Three-Dimensional Imaging}, doi = {10.25972/OPUS-15635}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-156355}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Since its first experimental implementation in 2005, single-molecule localization microscopy (SMLM) emerged as a versatile and powerful imaging tool for biological structures with nanometer resolution. By now, SMLM has compiled an extensive track-record of novel insights in sub- and inter- cellular organization.\\ Moreover, since all SMLM techniques rely on the analysis of emission patterns from isolated fluorophores, they inherently allocate molecular information \$per\$ \$definitionem\$.\\ Consequently, SMLM transitioned from its origin as pure high-resolution imaging instrument towards quantitative microscopy, where the key information medium is no longer the highly resolved image itself, but the raw localization data set.\\ The work presented in this thesis is part of the ongoing effort to translate those \$per\$ \$se\$ molecular information gained by SMLM imaging to insights into the structural organization of the targeted protein or even beyond. Although largely consistent in their objectives, the general distinction between global or segmentation clustering approaches on one side and particle averaging or meta-analyses techniques on the other is usually made.\\ During the course of my thesis, I designed, implemented and employed numerous quantitative approaches with varying degrees of complexity and fields of application.\\ \\ In my first major project, I analyzed the localization distribution of the integral protein gp210 of the nuclear pore complex (NPC) with an iterative \textit{k}-means algorithm. Relating the distinct localization statistics of separated gp210 domains to isolated fluorescent signals led, among others, to the conclusion that the anchoring ring of the NPC consists of 8 homo-dimers of gp210.\\ This is of particular significance, both because it answered a decades long standing question about the nature of the gp210 ring and it showcased the possibility to gain structural information well beyond the resolution capabilities of SMLM by crafty quantification approaches.\\ \\ The second major project reported comprises an extensive study of the synaptonemal complex (SNC) and linked cohesin complexes. Here, I employed a multi-level meta-analysis of the localization sets of various SNC proteins to facilitate the compilation of a novel model of the molecular organization of the major SNC components with so far unmatched extend and detail with isotropic three-dimensional resolution.\\ In a second venture, the two murine cohesin components SMC3 and STAG3 connected to the SNC were analyzed. Applying an adapted algorithm, considering the disperse nature of cohesins, led to the realization that there is an apparent polarization of those cohesin complexes in the SNC, as well as a possible sub-structure of STAG3 beyond the resolution capabilities of SMLM.\\ \\ Other minor projects connected to localization quantification included the study of plasma membrane glycans regarding their overall localization distribution and particular homogeneity as well as the investigation of two flotillin proteins in the membrane of bacteria, forming clusters of distinct shapes and sizes.\\ \\ Finally, a novel approach to three-dimensional SMLM is presented, employing the precise quantification of single molecule emitter intensities. This method, named TRABI, relies on the principles of aperture photometry which were improved for SMLM.\\ With TRABI it was shown, that widely used Gaussian fitting based localization software underestimates photon counts significantly. This mismatch was utilized as a \$z\$-dependent parameter, enabling the conversion of 2D SMLM data to a virtual 3D space. Furthermore it was demonstrated, that TRABI can be combined beneficially with a multi-plane detection scheme, resulting in superior performance regarding axial localization precision and resolution.\\ Additionally, TRABI has been subsequently employed to photometrically characterize a novel dye for SMLM, revealing superior photo-physical properties at the single-molecule level.\\ Following the conclusion of this thesis, the TRABI method and its applications remains subject of diverse ongoing research.}, subject = {Einzelmolek{\"u}lmikroskopie}, language = {en} } @article{FrankSchmittHovestadtetal.2017, author = {Frank, Erik Thomas and Schmitt, Thomas and Hovestadt, Thomas and Mitesser, Oliver and Stiegler, Jonas and Linsenmair, Karl Eduard}, title = {Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis}, series = {Science Advances}, volume = {3}, journal = {Science Advances}, number = {4}, doi = {10.1126/sciadv.1602187}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157933}, pages = {e1602187}, year = {2017}, abstract = {Predators of highly defensive prey likely develop cost-reducing adaptations. The ant Megaponera analis is a specialized termite predator, solely raiding termites of the subfamily Macrotermitinae (in this study, mostly colonies of Pseudocanthotermes sp.) at their foraging sites. The evolutionary arms race between termites and ants led to various defensive mechanisms in termites (for example, a caste specialized in fighting predators). Because M. analis incurs high injury/mortality risks when preying on termites, some risk-mitigating adaptations seem likely to have evolved. We show that a unique rescue behavior in M. analis, consisting of injured nestmates being carried back to the nest, reduces combat mortality. After a fight, injured ants are carried back by their nestmates; these ants have usually lost an extremity or have termites clinging to them and are able to recover within the nest. Injured ants that are forced experimentally to return without help, die in 32\% of the cases. Behavioral experiments show that two compounds, dimethyl disulfide and dimethyl trisulfide, present in the mandibular gland reservoirs, trigger the rescue behavior. A model accounting for this rescue behavior identifies the drivers favoring its evolution and estimates that rescuing enables maintenance of a 28.7\% larger colony size. Our results are the first to explore experimentally the adaptive value of this form of rescue behavior focused on injured nestmates in social insects and help us to identify evolutionary drivers responsible for this type of behavior to evolve in animals.}, language = {en} } @article{FrankKesnerLibertietal.2023, author = {Frank, Erik T. and Kesner, Lucie and Liberti, Joanito and Helleu, Quentin and LeBoeuf, Adria C. and Dascalu, Andrei and Sponsler, Douglas B. and Azuma, Fumika and Economo, Evan P. and Waridel, Patrice and Engel, Philipp and Schmitt, Thomas and Keller, Laurent}, title = {Targeted treatment of injured nestmates with antimicrobial compounds in an ant society}, series = {Nature Communications}, volume = {14}, journal = {Nature Communications}, doi = {10.1038/s41467-023-43885-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-358081}, year = {2023}, abstract = {Infected wounds pose a major mortality risk in animals. Injuries are common in the ant Megaponera analis, which raids pugnacious prey. Here we show that M. analis can determine when wounds are infected and treat them accordingly. By applying a variety of antimicrobial compounds and proteins secreted from the metapleural gland to infected wounds, workers reduce the mortality of infected individuals by 90\%. Chemical analyses showed that wound infection is associated with specific changes in the cuticular hydrocarbon profile, thereby likely allowing nestmates to diagnose the infection state of injured individuals and apply the appropriate antimicrobial treatment. This study demonstrates that M. analis ant societies use antimicrobial compounds produced in the metapleural glands to treat infected wounds and reduce nestmate mortality.}, language = {en} } @article{FrankDengjelWilflingetal.2015, author = {Frank, Daniel O. and Dengjel, J{\"o}rn and Wilfling, Florian and Kozjak-Pavlovic, Vera and H{\"a}cker, Georg and Weber, Arnim}, title = {The Pro-Apoptotic BH3-Only Protein Bim Interacts with Components of the Translocase of the Outer Mitochondrial Membrane (TOM)}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {4}, doi = {10.1371/journal.pone.0123341}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143301}, pages = {e0123341}, year = {2015}, abstract = {The pro-apoptotic Bcl-2-family protein Bim belongs to the BH3-only proteins known as initiators of apoptosis. Recent data show that Bim is constitutively inserted in the outer mitochondrial membrane via a C-terminal transmembrane anchor from where it can activate the effector of cytochrome c-release, Bax. To identify regulators of Bim-activity, we conducted a search for proteins interacting with Bim at mitochondria. We found an interaction of Bim with Tom70, Tom20 and more weakly with Tom40, all components of the Translocase of the Outer Membrane (TOM). In vitro import assays performed on tryptically digested yeast mitochondria showed reduced Bim insertion into the outer mitochondrial membrane (OMM) indicating that protein receptors may be involved in the import process. However, RNAi against components of TOM (Tom40, Tom70, Tom22 or Tom20) by siRNA, individually or in combination, did not consistently change the amount of Bim on HeLa mitochondria, either at steady state or upon de novo-induction. In support of this, the individual or combined knockdowns of TOM receptors also failed to alter the susceptibility of HeLa cells to Bim-induced apoptosis. In isolated yeast mitochondria, lack of Tom70 or the TOM-components Tom20 or Tom22 alone did not affect the import of Bim into the outer mitochondrial membrane. In yeast, expression of Bim can sensitize the cells to Bax-dependent killing. This sensitization was unaffected by the absence of Tom70 or by an experimental reduction in Tom40. Although thus the physiological role of the Bim-TOM-interaction remains unclear, TOM complex components do not seem to be essential for Bim insertion into the OMM. Nevertheless, this association should be noted and considered when the regulation of Bim in other cells and situations is investigated.}, language = {en} } @article{FranchiniJonesXiongetal.2018, author = {Franchini, Paolo and Jones, Julia C. and Xiong, Peiwen and Kneitz, Susanne and Gompert, Zachariah and Warren, Wesley C. and Walter, Ronald B. and Meyer, Axel and Schartl, Manfred}, title = {Long-term experimental hybridisation results in the evolution of a new sex chromosome in swordtail fish}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, doi = {10.1038/s41467-018-07648-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228396}, year = {2018}, abstract = {The remarkable diversity of sex determination mechanisms known in fish may be fuelled by exceptionally high rates of sex chromosome turnovers or transitions. However, the evolutionary causes and genomic mechanisms underlying this variation and instability are yet to be understood. Here we report on an over 30-year evolutionary experiment in which we tested the genomic consequences of hybridisation and selection between two Xiphophorus fish species with different sex chromosome systems. We find that introgression and imposing selection for pigmentation phenotypes results in the retention of an unexpectedly large maternally derived genomic region. During the hybridisation process, the sex-determining region of the X chromosome from one parental species was translocated to an autosome in the hybrids leading to the evolution of a new sex chromosome. Our results highlight the complexity of factors contributing to patterns observed in hybrid genomes, and we experimentally demonstrate that hybridisation can catalyze rapid evolution of a new sex chromosome.}, language = {en} } @phdthesis{Forstmeier2001, author = {Forstmeier, Wolfgang}, title = {Individual reproductive strategies in the dusky warbler (Phylloscopus fuscatus)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-1232}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {This study investigates mechanisms and consequences of sexual selection in a polygynous population of dusky warblers Phylloscopus fuscatus, breeding near Magadan in the Russian Far East. In particular, the study focuses on individual variation in the reproductive behaviours of both females and males. The mating system of this population is characterised by facultative polygyny (17 per cent of the males mated with more than one female), and by an outstandingly high rate of extra-pair paternity (45 per cent of the offspring was not sired by the social partner of the female). The occurrence of polygyny is best explained by the 'polygyny-threshold model' (PTM). A novel finding of this study is that female mating decisions follow a conditional strategy. First-year females that have no prior breeding experience prefer monogamy over territory quality, while older females more often mate polygynously. I argue that the costs of receiving no male help may be higher for inexperienced females, while the benefits of having a free choice between territories may be higher for individuals that know which territories had the highest breeding success in previous years. Furthermore, I find support for the existence of two female mating strategies. The 'emancipated' female which is not dependent on male help, is free to choose the best territory and the best copulation partners. The 'help-dependent' female, in contrast, is bound to find a partner who is willing to assist her with brood care, thus she will have to accept territories and genetic fathers of lesser quality. The most unexpected finding on female mating behaviours is that this dichotomy between emancipated and help-dependent females is accompanied by morphological specialisation, which indicates that there is genetic variation underlying these female mating strategies. Male mating behaviours are characterised by competition for ownership of the best territories and by advertisement of male quality to females, as these are the factors which largely determine male reproductive success. Male success in obtaining copulations depended on the quality of their song, a fact that explains why males spend most of the daytime singing during the period when females are fertile. Individuals that were able to maintain a relatively high sound amplitude during rapid frequency modulations were consistently preferred by females as copulation partners. Studies of physiological limitations on sound production suggest that such subtle differences in male singing performance can provide an honest reflection of male quality. The present study is the first to indicate that females may judge the quality of a male's song by his performance in sound production. Quality of song was also related to winter survival, which suggests that females can enhance the viability of their offspring by seeking extra-pair fertilisations from good singers (good-genes hypothesis). In general, the present study demonstrates that a complete understanding of avian mating systems is not possible without a detailed analysis of alternative behavioural strategies and of how individuals adjust their reproductive tactics according to their individual needs and abilities.}, subject = {Laubs{\"a}nger}, language = {en} }