The present thesis investigated memory load and memory decay in auditory working memory. Alpha power as a marker for memory load served as the primary indicator for load and decay fluctuations hypothetically reflecting functional inhibition of irrelevant information. Memory load was induced by presenting auditory signals (syllables and pure-tone sequences) in noise because speech-in-noise has been shown before to increase memory load. The aim of the thesis was to assess with magnetoencephalography whether a-priori temporal expectations for the onset-time of a to-be-remembered stimulus reduces memory load. It was reported previously that top-down modulations such as spatial expectations reduce memory load and improve memory performance. However, this effect has neither been investigated with temporal expectations nor in the auditory domain. The present thesis showed that temporal expectations for a syllable in noise reduced memory load. Reduced alpha power during stimulus maintenance as well as improved performance indicated the decrease in memory load. Alpha power effects emerged from the right cingulo-opercular network, presumably reflecting a reduced need for functional inhibition. Critically, symbolic cues induced temporal expectations. This effect could not be replicated for clear speech. However, more implicit temporal expectations based on the passage of time elicited a similar decrease in alpha power for clear speech reflecting reduced memory load. Memory decay was assessed with variable delay phases in an auditory sensory memory task with pure-tone sequences. Similarly to memory performance, alpha power decreased with longer delay phases. Critically, temporal expectations counteracted memory decay and led to more sustained performance as well as alpha power across different delay phases. These alpha-power effects were localized to frontal and parietal attention networks as well as primary auditory and visual sensory areas. This implies the involvement of different brain regions relevant for encoding and maintenance in auditory memory and questions a parsimonious functional inhibition explanation. A correlation of alpha power and behavioral performance underpinned the importance of alpha power for auditory working memory. Altogether, the results of the present thesis provide evidence for a beneficial effect of a-priori temporal expectations for an auditory signal on working memory. Moreover, alpha dynamics were shown to be a distinct marker for the neural efficiency of managing working memory limitations.

This thesis investigates how the neural system instantiates selective attention to speech in challenging acoustic conditions, such as spectral degradation and the presence of background noise. Four studies using behavioural measures, magneto- and electroencephalography (M/EEG) recordings were conducted in younger (20–30 years) and older participants (60–80 years). The overall results can be summarized as follows. An EEG experiment demonstrated that slow negative potentials reflect participants’ enhanced allocation of attention when they are faced with more degraded acoustics. This basic mechanism of attention allocation was preserved at an older age. A follow-up experiment in younger listeners indicated that attention allocation can be further enhanced in a context of increased task-relevance through monetary incentives. A subsequent study focused on brain oscillatory dynamics in a demanding speech comprehension task. The power of neural alpha oscillations (~10 Hz) reflected a decrease in demands on attention with increasing acoustic detail and critically also with increasing predictiveness of the upcoming speech content. Older listeners’ behavioural responses and alpha power dynamics were stronger affected by acoustic detail compared with younger listeners, indicating that selective attention at an older age is particularly dependent on the sensory input signal. An additional analysis of listeners’ neural phase-locking to the temporal envelopes of attended speech and unattended background speech revealed that younger and older listeners show a similar segregation of attended and unattended speech on a neural level. A dichotic listening experiment in the MEG aimed at investigating how neural alpha oscillations support selective attention to speech. Lateralized alpha power modulations in parietal and auditory cortex regions predicted listeners’ focus of attention (i.e., left vs right). This suggests that alpha oscillations implement an attentional filter mechanism to enhance the signal and to suppress noise. A final behavioural study asked whether acoustic and semantic aspects of task-irrelevant speech determine how much it interferes with attention to task-relevant speech. Results demonstrated that younger and older adults were more distracted when acoustic detail of irrelevant speech was enhanced, whereas predictiveness of irrelevant speech had no effect. All findings of this thesis are integrated in an initial framework for the role of attention for speech comprehension under demanding acoustic conditions.

Background: The specification of metadata in clinical and epidemiological study projects absorbs significant expense. The validity and quality of the collected data depend heavily on the precise and semantical correct representation of their metadata. In various research organizations, which are planning and coordinating studies, the required metadata are specified differently, depending on many conditions, e.g., on the used study management software. The latter does not always meet the needs of a particular research organization, e.g., with respect to the relevant metadata attributes and structuring possibilities. Methods: The objective of the research, set forth in this paper, is the development of a new approach for ontology-based representation and management of metadata. The basic features of this approach are demonstrated by the software tool OntoStudyEdit (OSE). The OSE is designed and developed according to the three ontology method. This method for developing software is based on the interactions of three different kinds of ontologies: a task ontology, a domain ontology and a top-level ontology. Results: The OSE can be easily adapted to different requirements, and it supports an ontologically founded representation and efficient management of metadata. The metadata specifications can by imported from various sources; they can be edited with the OSE, and they can be exported in/to several formats, which are used, e.g., by different study management software. Conclusions: Advantages of this approach are the adaptability of the OSE by integrating suitable domain ontologies, the ontological specification of mappings between the import/export formats and the DO, the specification of the study metadata in a uniform manner and its reuse in different research projects, and an intuitive data entry for non-expert users.

The progress in biotechnological disciplines such as metabolic engineering or synthetic biology increased the interest of chemical and pharmaceutical industries to implement microbial processes for chemical synthesis. However, most microorganisms, e.g., Escherichia coli or Saccharomyces cerevisiae, used in biotechnological applications are not evolved by nature for the production of industrially relevant compounds, which are often hydrophobic, non-charged, volatile, or toxic to the microbial organisms. Bioprocess design relies on an integrated approach addressing pathway, cellular, reaction, and process engineering to combine the results of natural evolution with the demands of industrial applicability. In this thesis, the microbial de novo production and selective oxyfunctionalization of the highly volatile isoprenoid limonene has been investigated as a model system featuring reactants with challenging physicochemical characteristics. Key constraints that limit limonene biosynthesis and its oxyfunctionalization in recombinant E. coli, related to genetics, physiology, and reaction engineering, were identified and relieved.

Denisova Cave is located in the Altai mountains of Russia. Excavations from this cave have yielded two large hominin molars and three hominin phalanxes from the Pleistocene. One of the phalanxes (Denisova 3) had extraordinary DNA preservation allowing the sequencing of high quality nuclear and mitochondrial DNA (mtDNA) genomes and has been shown to belong to a young girl from hereto unknown sister group of Neandertals, called Denisovans. The mtDNA of Denisova 3 surprisingly split from the mtDNA ancestor of modern humans and Neandertals twice as long ago as the split of modern humans and Neandertals. The mtDNA of one of the molars (Denisova 4) was also sequenced and differs at only two positions from the mtDNA of Denisova 3. A second phalanx (Altai 1) also yielded a high quality genome, and was a Neandertal. While Neandertals show an admixture signal of 1-4% into present-day non-Africans, Denisovans show an admixture of up to 5% in present-day Oceanians, and to a much lesser extent East Asians. This thesis encompasses two studies. In the first study, we sequenced the complete mtDNA genome of the additional molar (Denisova 8), as well as a few megabases of nuclear DNA from Denisova 4 and Denisova 8. While the mtDNA of Denisova 8 is clearly of the Denisova type, its branch to the most recent common ancestor of Denisovans is half as long as the branch leading to Denisova 3 or Denisova 4, indicating that Denisova 8 lived many millenia before the other two. Both Denisova 4 and 8 fall together with Denisova 3 based on nuclear DNA, bringing the number of known Denisovans from one to three. In the second study, we sequenced an almost complete mtDNA and a few megabases of nuclear DNA from the third hominin phalanx from Denisova Cave, Altai 2. Both the mtDNA and the nuclear DNA show Altai 2 to be a Neandertal. The mtDNA also showed the presence of substantial Pleistocene spotted hyena contamination. Low levels of spotted hyena contamination were also found in Altai 1, Denisova 3 and Denisova 4. Partial mtDNA genomes of the contaminating spotted hyenas from these four hominins were compared to mtDNA genomes of other extant and extinct spotted hyenas. We show that the spotted hyenas that contaminated the two Denisovans come from a population of spotted hyenas found in Pleistocene Europe as well as present-day Africa, while the spotted hyenas that contaminated Altai 2, and possibly Altai 1, come from a population of spotted hyenas found in Pleisticene eastern Russia and northern China. This indicates that Denisova Cave was a meeting point of eastern and western hominins as well as eastern and western spotted hyena populations.

The PhD thesis addresses the analysis of GABA and glycine cotransmitting (GgC) neurons in the Pre-Bötzinger Complex (PBC), a region important for rhythm generation of the respiration. GgC neurons were identified in the PBC using different approaches including single-cell RT-PCR and immunohistochemistry. Furthermore, novel transgenic mouse-lines were generated to facilitate the analysis of these neurons in-vivo and in living-tissue preparations: The mouse-line Cofluor allows the identification of GABAergic, glycinergic as well as GgC neurons by the expression of different fluorescent proteins. This mouse-line was used to investigate the number of cells of each neuron type during development from E15.5 to 2.5 month revealing a decrease of GgC neurons paralleled by an increase of glycinergic and GABAergic neurons. The mouse line COTRIND expresses the tamoxifen-inducible Split-CreERT2 system exclusively in GgC neurons allowing for the permanent labelling of these neurons with the Red Fluorescent Protein at the time-point of tamoxifen application. In COTRIND mice, GgC neurons were irreversibly labelled at the age of P1/P2 and analysed at the age of three days as well as after 2.5 month to investigate their fate by using immunohistochemistry. It was found that GgC neurons differentiated to mostly glycinergic neurons and to a minor percentage to GABAergic neurons whereas some GgC neurons remained GgC neurons. The results obtained from this study disclosed the presence of GgC neurons in the PBC of mice and their development from the embryonic day 15.5 to the adult stage. Furthermore, the inducible Split-CreERT2 system was for the first time established in transgenic COTRIND mice and found to be functional in vivo without leakage. With the novel transgenic mouse lines the present work provides tools for the analysis of GgC neurons in the PBC and contributes to the characterisation of this neuron type including the role for rhythm generation of the respiration.

Expression and interaction of desmosomal components and keratins provide stable cell cohesion and protect the epidermis against various types of stress. The differentiation-specific isotype composition of the keratin cytoskeleton and desmosomes is regarded as major determinant of adhesive strength. However, the functional significance of individual keratins for the composition and adhesion of desmosomes has not been addressed in full. To overcome keratin redundancy following deletion of individual keratin genes, the entire type II or type I keratin cluster was deleted, resulting in the absence of keratin filaments in epidermal keratinocytes. The comparison of mouse keratinocyte cell lines lacking all keratins or re-expressing distinct keratin isotypes provides an excellent model to examine keratin contribution to the formation and stability of desmosomes. In support with the reported phenotype in vivo, desmosomes assemble in the absence of keratins but are endocytosed at accelerated rates. The internalization of desmosomes is regulated by PKCα-mediated desmoplakin phosphorylation, rendering epithelial sheets highly susceptible to mechanical stress in cell culture. Re-expression of the keratin pair K5/K14, inhibition of PKCα activity, or blocking of endocytosis reconstituted both desmosome localization at the plasma membrane and epithelial adhesion. The data support a model whereby K5/K14 sequesters RACK1, which can bind PKCα and thereby limits DP phosphorylation, promoting desmosome stability/maintenance and intercellular adhesive strength. To investigate the isotype-specific function of keratins, the respective contribution of K5/K14 or K6/K17 to desmosome adhesion, upon their stable re-expression in keratinocytes lacking all keratins was analyzed. This revealed that K5/K14 support stable desmosomes, whereas expression of “wound healing” keratins K6/K17 induce PKCα-mediated desmosome disassembly and subsequent destabilization of epithelial sheets accompanied by faster wound closure. Furthermore, analysis of adherens junctions and actin organization in keratin-free keratinocytes demonstrated a role of keratins in reorganization of the actin cytoskeleton and maturation of adherens junctions. This study identified a hitherto unknown mechanism by which keratins control intercellular adhesion, with potential implications for wound healing, tumor invasion and keratinopathies, settings in which diminished cell adhesion facilitates tissue fragility and neoplastic growth.

Siberia is an ideal region for exploring population histories from a molecular anthropological perspective given the diverse human populations, in terms of linguistic affiliation and lifestyle, currently inhabiting this geographically large region. As such, this thesis explores new methodologies for the investigation of the genetic histories of Siberian populations. While previous genetic work in this area of the world was able to provide detailed insights into paternal histories based on Y chromosomal data, it was not as successful on the maternal side. There existed difficulties in exploring the complex maternal demographic histories due to high levels of sequence identity between individuals in different populations when using only a very small region of the mitochondrial DNA (mtDNA), known as the hypervariable region I (HV1). This realization led to the initial focus of this dissertation which was to identify and test improved methods of sequencing entire mtDNA genomes. This was necessary because the mtDNA genomes that were published for human Siberian populations and across the globe prior to the work described here were chosen based on specific sub-sample selection criteria that introduced an ascertainment bias rendering them unusable for population-wide analyses. After testing multiple next generation DNA sequencing methods, I helped develop a sequencing library preparation method based on multiplexing and hybridization enrichment of mtDNAs for sequencing by synthesis that has since become widely used in labs across the globe. Comparing the same samples sequenced by both the traditional and new methods for five ethnolinguistic populations showed that these new methods were robust and could lead to different inferences about population histories while avoiding a sampling bias. Based on the results of this thesis it is now recommended for researchers to sequence complete mtDNA genomes for all relevant samples within a collection. By applying these methods to additional Siberian populations it was possible to better describe maternal population contact and identify demographic changes over time. This additional information allowed for the identification of putative drops in the maternal effective population sizes in the Siberian populations examined here. When examining the potential migrations and population contact between Turkic-speaking Yakuts and the Tungusic-speaking Even and Evenks, there exists a differential sharing of haplotypes suggesting that the Tungusic speaking populations herein were already in the northern region and split prior to the expansion of the Yakuts into their territory. The putative origin of the Yakuts as being around Lake Baikal was given additional support from the analyses included in this study and the origins of the Dolgans were shown to predominately include the admixture of Yakuts and Evenks.

Direct fitness is measured as the number of surviving offspring. Thus adult males may try to produce as many offspring as possible or to increase the survival of their offspring. Recent findings have shown the many potential benefits of fathers’ presence and support on infants’ development and survival. However, little is known about the influence of socio-ecological factors on male-infant interactions. The main aim of this thesis was therefore to investigate male-infant interactions in wild crested macaques (Macaca nigra). In particular, we aimed to examine the affiliative and agonistic interactions taking place in this species, along with the factors influencing these interactions and offspring survival. Data collection for this thesis took place in the Tangkoko-Duasudara Reserve in Sulawesi, Indonesia, on 3 wild groups of crested macaques. For the first study, data were collected on migrations, births, disappearances, and encounters between groups over 5 years. We analyzed the influence of socio-ecological factors (e.g. rainfall, alpha-male position takeover, and male hierarchy stability) on pre- and post-natal loss. The results showed that high infant mortality was mainly associated to male alpha-position takeover, which suggests that infanticide may indeed occur in this species. In addition, we found that female within-group competition for food sources and between-group resource defense influenced fetal and infant loss. Based on these findings, we were interested to see whether fathers protected their own offspring against male attacks. Thus, in the second study, we investigated the social determinants and characteristics of male-infant affiliations. Our results indicate that adult males and infants form preferential association, and that infants initiate the majority of male-infant affiliations. Infants initiated affiliations mainly towards a high ranking male or a male in a close relationship with their mother. In addition, infants affiliated mainly with adult males in the absence of their mother, while males affiliated mostly with infants when the infants‘ mother was present in proximity. Furthermore, males initiated affiliations towards an infant when they held a high rank or when they had a strong bond with the infant‘s mother. Interestingly, paternity did not affect male-infant affiliations. In conclusion, these studies provide insights in the specifics of both infant survival strategies and male reproductive strategies. In addition, we show that infants are active agents in establishing and maintaining preferential relationships with males. This thesis, thus, confirm that male-infant interactions, although rare, have a strong influence both on males’ and infants’ direct fitness.:Contents ........................................................................................................................................ 5 List of Figures .............................................................................................................................. 7 List of Tables ................................................................................................................................ 8 Summary ....................................................................................................................................... 9 Zusammenfassung .................................................................................................................. 13 1 General Introduction .......................................................................................................... 17 1.1 Infants and adult males in mammals ...................................................................... 18 1.2 Primate males’ use and abuse of infants ................................................................ 19 1.3 Male care and paternal care in primates ............................................................... 20 1.4 Crested macaques as study species ......................................................................... 21 1.5 Aims of this thesis ........................................................................................................... 23 2 Social and ecological factors influencing offspring survival in wild macaques ................................................................................................................................... 25 2.1 Abstract ............................................................................................................................... 26 2.2 Introduction ...................................................................................................................... 26 2.3 Methods .............................................................................................................................. 29 2.4 Results ................................................................................................................................. 34 2.5 Discussion .......................................................................................................................... 37 3 Mother-male bond, but not paternity, influences male-infant affiliation in wild crested macaques .......................................................................................................... 45 3.1 Abstract ............................................................................................................................... 46 3.2 Introduction ...................................................................................................................... 46 3.3 Methods .............................................................................................................................. 50 3.4 Results ................................................................................................................................. 58 3.5 Discussion .......................................................................................................................... 61 4 Thesis Conclusion ................................................................................................................ 71 Appendices ................................................................................................................................ 75 Supplementary figure and tables for Chapter 2 ......................................................... 76 Supplementary methods and tables for Chapter 3 ................................................... 79 Bibliography ............................................................................................................................. 83 Acknowledgements ................................................................................................................ 99 Contributions of co-authors .............................................................................................. 101 Curriculum vitae .................................................................................................................... 105 Publications and conference contributions ................................................................. 107 Selbstständigkeitserklärung ............................................................................................. 109

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