Fostering team innovation is increasingly an important leadership function. However, the empirical evidence for the role of transformational leadership in engendering team innovation is scarce and mixed. To address this issue, the authors link transformational leadership theory to principles of M. A. West's (1990) team climate theory and propose an integrated model for the relationship between transformational leadership and team innovation. This model involves support for innovation as a mediating process and climate for excellence as a moderator. Results from a study of 33 research and development teams confirmed that transformational leadership works through support for innovation, which in turn interacts with climate for excellence such that support for innovation enhances team innovation only when climate for excellence is high.

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This study sheds light on the mediating processes by which transformational leadership influences follower performance and innovation, respectively. We hypothesize that transformational leaders boost follower performance by stimulating organizational citizenship behavior, whereas they enhance follower innovation by triggering controversial discussion of task related issues (debate). On the contrary, we do not expect these mediating effects to hold for the relationship between transactional leadership and follower performance and innovation, respectively. Our hypotheses were confirmed in an empirical study of N = 91 leaders from 91 German companies. Conclusions for leadership research are drawn. Key words: debate, innovation, organizational citizenship behavior, transactional leadership, transformational leadership

The migration of zebrafish primordial germ cells (PGCs) is directed by SDF-1a and serves as a model for long-range chemokine-guided cell migration. Whereas the development and migration of zebrafish PGCs have been studied in great detail starting at mid-gastrulation stages when the cells exhibit guided active migration [7-8 hours post fertilization (hpf)], earlier stages have not yet been examined. Here we show that the PGCs acquire competence to respond to the chemokine following discrete maturation steps. Using the promoter of the novel gene askopos and RNA elements of nanos1 to drive GFP expression in PGCs, we found that immediately after their specification (about 3 hpf) PGCs exhibit simple cell shape. This stage is followed by a phase at which the cells assume complex morphology yet they neither change their position nor do they respond to SDF-1a. During the third phase, a transition into a `migratory stage' occurs as PGCs become responsive to directional cues provided by somatic cells secreting the chemokine SDF-1a. This transition depends on zygotic transcription and on the function of the RNA-binding protein Dead end and is correlated with down regulation of the cell adhesion molecule E-cadherin. These distinctive morphological and molecular alterations could represent a general occurrence in similar processes critical for development and disease.

Leadership research has focused on the positive effects of transformational and charismatic leadership but has neglected the negative side effects. Addressing this gap, we analysed followers' dependency on the leader as a relevant negative side effect in the relationship between transformational leadership and followers' creativity and developed an integrative framework on parallel positive and negative effects of transformational leadership. As expected, results from a study with 416 R&D employees showed that transformational leadership promotes followers' creativity but at the same time increases followers' dependency which in turn reduces their creativity. This negative indirect effect attenuates the positive influence of transformational leadership on followers' creativity.