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While entrepreneurship researchers agree that institutions 'matter' for entrepreneurship, they also have a rather encompassing understanding of institutions as almost any external factor that influences entrepreneurship. Ultimately, this literature thus comes up with a long list of institutional factors that may explain entrepreneurial differences between countries. But which institutions are most influential? How do these institutions relate to different types of entrepreneurship? And to what extent are institutions complementary to each other in the way they sustain different entrepreneurship types? The literature on 'Varieties-of-Capitalism' (VoC) offers a parsimonious theoretical framework to address these questions. Based on the VoC literature, we theoretically derive a consistent set of institutional indicators that can explain differences in entrepreneurship types between countries. Based on principal component and cluster analyses, we illustrate how 21 Western developed economies cluster around four distinct institutional settings. Furthermore, we use simple OLS regressions to show how these institutional constellations are related to different types of entrepreneurship. We conclude that four different 'Varieties of Entrepreneurship' can be identified across the Western world. The main implication of our findings is that a 'perfect' institutional constellation, equally facilitating different types of entrepreneurship, does not exist. Policy-makers seeking to stimulate entrepreneurship are thus faced with the trade-off of targeting policy reforms to that entrepreneurship type they intend to promote—at the expense of other types of entrepreneurship and the broader societal consequences such reforms will have.

Research into the link between national institutions and entrepreneurship is characterized by three shortcomings: First, clear-cut concepts of institutions are rare. Second, a parsimonious understanding of how a few core institutions influence entrepreneurship is missing. Third, scholars often ignore that incrementally innovative ventures constitute a distinct (and under-researched) type of entrepreneurship next to the (over-researched) form of radically innovative, high-growth or high-tech entrepreneurship. By addressing these three shortcomings, the Varieties-of-Capitalism (VoC) literature can explain how a core group of distinct national institutions facilitate the development of different types of entrepreneurship between countries. In particular, the VoC framework illustrates the comparative institutional advantage that continental European economies offer to incrementally innovative ventures. Applications of the VoC reasoning to entrepreneurship studies would thus allow researchers to, first, perform focused rather than eclectic analyses of institutional influences on entrepreneurship. Second, it would pave the way for research into institutionally induced equifinality. Third, entrepreneurship research could move away from its wishful ideology displaying radically innovative entrepreneurship as the most desirable form of entrepreneurship. As a consequence, policymakers could target entrepreneurial support measures more specifically to their economy’s institutional environment.

External linkages allow nascent ventures to access crucial resources during the process of new product development. Forming external linkages can substantially contribute to a venture’s performance. However, little is known about the paths of external linkage formation, as well as the circumstances that drive the choice to pursue one rather than another path. This gap deserves further investigation, because we do not know whether insights developed for incumbent firms also apply to nascent ventures: To address this gap, we explore a novel dataset of 370 venture creation processes. Using sequence analyses based on optimal matching techniques and cluster analyses, we reveal that nascent ventures pursue one of overall four distinct paths of linkage formation activities during new product development. Contrary to the findings of the strategy literature, we find that if nascent ventures engage in external linkages at all, they do not combine exploration- and exploitation-oriented linkages but form either exploration- or exploitation-oriented linkages. Additional regression analyses highlight the circumstances that lead nascent ventures to pursue one rather than the other pathways. Taken together, our analyses point out that resource scarcity constitutes an important factor shaping the linkage formation activities of nascent ventures. Accordingly, we show that nascent ventures tend not to optimize by adding complementary knowledge to the firm’s knowledge base but rather to extend the existing knowledge base—a strategy which we call bricolage.

While entrepreneurship research theorizing about the team formation in start-up ventures exists, such studies mostly focus on different outcomes of team formation, for example the number of employees. Questions about how team formation processes unfold and the factors, such as labor-market institutions, influencing their evolvement remain unanswered. To address this research gap, we analyze the venture creation processes of 344 ventures in Germany and the USA, offering particularly typical examples of countries with regulated and deregulated labor-market institutions respectively. Based on optimal matching techniques, we illustrate how team formation processes differ over time in terms of founder and employee involvement and the hiring of service providers. Furthermore, we use binary logistic regressions to identify the extent to which national labor-market institutions account for these differences.

Gram-negative bacteria maintain an intrinsic resistance mechanism against entry of noxious compounds by utilizing highly efficient efflux pumps. The E. coli AcrAB-TolC drug efflux pump contains the inner membrane H + /drug antiporter AcrB comprising three functionally interdependent protomers, cycling consecutively through the loose (L), tight (T) and open (O) state during cooperative catalysis. Here, we present 13 X-ray structures of AcrB in intermediate states of the transport cycle. Structure-based mutational analysis combined with drug susceptibility assays indicate that drugs are guided through dedicated transport channels toward the drug binding pockets. A co-structure obtained in the combined presence of erythromycin, linezolid, oxacillin and fusidic acid shows binding of fusidic acid deeply inside the T protomer transmembrane domain. Thiol cross-link substrate protection assays indicate that this transmembrane domain-binding site can also accommodate oxacillin or novobiocin but not erythromycin or linezolid. AcrB-mediated drug transport is suggested to be allosterically modulated in presence of multiple drugs. Gram-negative bacteria can display intrinsic antibiotic resistance due to the action of tripartite efflux pumps, which include a H + /drug antiporter component. Here, the authors present a structure-function analysis of antiporter AcrB in intermediate states of the transport cycle, showing novel drug-binding sites and transport pathways.

Efflux transporters of the RND family confer resistance to multiple antibiotics in Gram-negative bacteria. Here, we identify and chemically optimize pyridylpiperazine-based compounds that potentiate antibiotic activity in E. coli through inhibition of its primary RND transporter, AcrAB-TolC. Characterisation of resistant E. coli mutants and structural biology analyses indicate that the compounds bind to a unique site on the transmembrane domain of the AcrB L protomer, lined by key catalytic residues involved in proton relay. Molecular dynamics simulations suggest that the inhibitors access this binding pocket from the cytoplasm via a channel exclusively present in the AcrB L protomer. Thus, our work unveils a class of allosteric efflux-pump inhibitors that likely act by preventing the functional catalytic cycle of the RND pump. Efflux transporters of the RND family confer resistance to multiple antibiotics in Gram-negative bacteria. Here, the authors identify pyridylpiperazine-based compounds that potentiate antibiotic activity in E. coli through allosteric inhibition of its primary RND transporter.

Isolating pure microbial cultures and cultivating them in the laboratory on defined media is used to more fully characterize the metabolism and physiology of organisms. However, identifying an appropriate growth medium for a novel isolate remains a challenging task. Even organisms with sequenced and annotated genomes can be difficult to grow, despite our ability to build genome-scale metabolic networks that connect genomic data with metabolic function. The scientific literature is scattered with information about defined growth media used successfully for cultivating a wide variety of organisms, but to date there exists no centralized repository to inform efforts to cultivate less characterized organisms by bridging the gap between genomic data and compound composition for growth media. Here we present MediaDB, a manually curated database of defined media that have been used for cultivating organisms with sequenced genomes, with an emphasis on organisms with metabolic network models. The database is accessible online, can be queried by keyword searches or downloaded in its entirety, and can generate exportable individual media formulation files. The data assembled in MediaDB facilitate comparative studies of organism growth media, serve as a starting point for formulating novel growth media, and contribute to formulating media for in silico investigation of metabolic networks. MediaDB is freely available for public use at https://mediadb.systemsbiology.net.

UML activity diagrams and state machines are both used for modeling system behavior from the user perspective and are frequently the basis for deriving system test cases. In practice, system test cases are often derived manually from UML activity diagrams or state machines. For this task, comprehensibility of respective models is essential and a relevant question for practice to support model selection and design, as well as subsequent test derivation. Therefore, the objective of this paper is to compare the comprehensibility of UML activity diagrams and state machines during manual test case derivation. We investigate the comprehensibility of UML activity diagrams and state machines in a controlled student experiment. Three measures for comprehensibility have been investigated: (1) the self-assessed comprehensibility, (2) the actual comprehensibility measured by the correctness of answers to comprehensibility questions, and (3) the number of errors made during test case derivation. The experiment was performed and internally replicated with overall 84 participants divided into three groups at two institutions. Our experiment indicates that activity diagrams are more comprehensible but also more error-prone with regard to manual test case derivation and discusses how these results can improve system modeling and test case design.

As economic internationalization advances, the question of how firms cope with increasing pressure for competitiveness gains momentum. While scholars agree that firms need a competitive advantage, they debate whether firms exploit the comparative advantage of their economy and converge on that strategy facilitated by national institutions. 'No', argue strategic management proponents of the resource-based view. 'Yes', claim contributors to the competitiveness literature. The author's micro-level studies of these opposing views do not find evidence for a strong, widespread convergence by the firms in one economy to the same institutionally supported strategy. The discrepancies between these findings and the analyses of the competitiveness literature are attributed to differences in the indicators employed to measure corporate strategies. Whenever macro-level indicators are used, the related loss of information on micro-level variety entails that convergence effects are more pronounced – possibly exaggerated.