The expression of neuropeptides is often extremely restricted in the nervous system, making them powerful markers for addressing cell specification . In the developing Drosophila ventral nerve cord, only six cells, the Ap4 neurons, of some 10,000 neurons, express the neuropeptide FMRFamide (FMRFa). Each Ap4/FMRFa neuron is the last-born cell generated by an identifiable and wellstudied progenitor cell, neuroblast 5-6 (NB5-6T). The restricted expression of FMRFa and the wealth of information regarding its gene regulation and Ap4 neuron specification makes FMRFa a valuable readout for addressing many aspects of neural development, i.e., spatial and temporal patterning cues, cell cycle control, cell specification, axon transport, and retrograde signaling. To this end, we have conducted a forward genetic screen utilizing an Ap4-specific FMRFa-eGFP transgenic reporter as our readout. A total of 9781 EMS-mutated chromosomes were screened for perturbations in FMRFa-eGFP expression, and 611 mutants were identified. Seventynine of the strongest mutants were mapped down to the affected gene by deficiency mapping or whole-genome sequencing. We isolated novel alleles for previously known FMRFa regulators, confirming the validity of the screen. In addition, we identified novel essential genes, including several with previously undefined functions in neural development. Our identification of genes affecting most major steps required for successful terminal differentiation of Ap4 neurons provides a comprehensive view of the genetic flow controlling the generation of highly unique neuronal cell types in the developing nervous system. KEYWORDS Drosophila; CNS development; neural cell fate specification; forward genetic screening; FMRFamide D URING nervous system development, a restricted number of progenitors generate the vast number of neurons and glia that build the mature central nervous system (CNS). The final identity of a specific neuron is dependent upon a complex series of regulatory steps, including spatial and temporal cues, asymmetric cell division, and terminal cell fate determinants (Allan and Thor 2015). In addition to the generation of a myriad of unique cell fates, each neural subtype furthermore is generated in precise numbers, and thus both proliferation and apoptosis are tightly regulated during development. In spite of tremendous progress during the last decades in deciphering these regulatory events, our understanding of how they integrate within the context of any specific neuronal lineage to ensure final cell specification and cell number is still fragmentary.The Drosophila melanogaster CNS can be subdivided into the brain and the ventral nerve cord (VNC). The VNC is formed from the ventral part of the neuroectoderm by highly conserved anterior-posterior and dorsal-ventral patterning of the embryo (Skeath 1999;Skeath and Thor 2003). The VNC can be subdivided into three thoracic and 10 abdominal segments (Birkholz et al. 2013). During early embryogenesis 30 progenitors, denoted neuroblasts (NBs), a...

Neural progenitor cells, in both vertebrates and invertebrates, go through temporal competence changes, evidenced by the generation of different classes of neurons and glia at different time points (Okano and Temple, 2009). These programmed changes are likely to be controlled by a combination of both extrinsic and intrinsic cues, and evidence points to the existence of both mechanisms in vertebrates and invertebrates. With respect to intrinsic cues, major progress has been made in the Drosophila melanogaster system, in particular in the embryonic ventral nerve cord (VNC). Here, temporal competence changes have been shown to be under control of an intrinsic temporal cascade of transcription factors, the temporal gene cascade (Brody and Odenwald, 2002;Jacob et al., 2008;Pearson and Doe, 2004). This cascade consist of the sequential expression, and function, of the Hunchback (Hb), Kruppel (Kr), Nubbin and Pdm2 (denoted collectively Pdm herein), Castor (Cas) and Grainy head (Grh) transcription factors, in a HbrKrrPdmrCasrGrh cascade. The precise progression of this cascade is an effect of mutually activating and repressing actions of the factors upon each other. In addition, studies have also identified factors that facilitate this progression, i.e. 'switching factors'. Here, the seven up (svp) and distal antenna/distal antenna related (collectively referred to as dan herein) genes have been shown to play important roles in ensuring the switch from HbrKr, by suppressing Hb (Kanai et al., 2005;Kohwi et al., 2011;Mettler et al., 2006). Both Svp and Dan display a second wave of expression, but their function here is unknown. Finally, our previous studies have also identified the existence of so-called 'sub-temporal' genes, which act downstream of the temporal genes, do not regulate temporal genes, and act to sub-divide larger temporal windows (Baumgardt et al., 2009). However, in spite of the progress in understanding temporal competence changes, it is not clear how neuroblasts switch from one competence window to the next, how window size is controlled and how windows are subdivided. Moreover, recent mathematical modelling of the temporal cascades, indicate the existence of additional players involved in the temporal competence changes observed in vivo (Nakajima et al., 2010).To address these issues, we are using the Drosophila embryonic thoracic neuroblast 5-6 (NB5-6T) as a model. This neuroblast, which can be readily identified by the specific expression of reporter genes under the control of an enhancer fragment from the ladybird early gene [lbe(K)] (De Graeve et al., 2004), is generated in each of the six thoracic VNC hemisegments. Each NB5-6T produces a mixed lineage of 20 cells, and the four last cells to be born are a set of four interneurons expressing the Apterous (Ap) LIM-homeodomain transcription factor: the Ap neurons (Baumgardt et al., 2009). The four Ap neurons can be further subdivided into three different neuronal sub-types: the Ap1/Nplp1 and Ap4/FMRFa neurons, expressing the Nplp1 and FMRFamide neurop...

There is evidence from in vitro studies that inflammatory messengers influence the release of stress hormone via direct effects on the adrenal gland; however, the mechanisms underlying these effects in the intact organism are unknown. Here we demonstrate that systemic inflammation in rats elicited by iv injection of lipopolysaccharide results in dynamic changes in the adrenal immune cell population, implying a rapid depletion of dendritic cells in the inner cortical layer and the recruitment of immature cells to the outer layers. These changes are accompanied by an induced production of IL-1beta and IL-1 receptor type 1 as well as cyclooxygenase-2 and microsomal prostaglandin E synthase-1 in these cells, implying local cytokine-mediated prostaglandin E(2) production in the adrenals, which also displayed prostaglandin E(2) receptors of subtypes 1 and 3 in the cortex and medulla. The IL-1beta expression was also induced by systemically administrated IL-1beta and was in both cases attenuated by IL-1 receptor antagonist, consistent with an autocrine signaling loop. IL-1beta similarly induced expression of cyclooxygenase-2, but the cyclooxygenase-2 expression was, in contrast, further enhanced by IL-1 receptor antagonist. These data demonstrate a mechanism by which systemic inflammatory agents activate an intrinsically regulated local signaling circuit that may influence the adrenals' response to immune stress and may help explain the dissociation between plasma levels of ACTH and corticosteroids during chronic immune perturbations.

What is the nature of new product introduction strategies of multinational corporations, large, medium, and small enterprises? Based on data on 237 product/brand launches collected from four business periodicals between January 1991 and July 1992, this article by Abraham Koshy and Anna Angel focuses on this issue.

totic and mitotic cells, neuronal and glial nuclei. DeadEasy software employs image filtering and mathematical morphology techniques. It counts cell number from a confocal stack of images, by analysing cells in 2D and 3D throughout the whole stack. Quantification is automatic, accurate, objective and very fast, enabling reliable comparisons of multiple specimens of diverse genotypes. Although DeadEasy was developed and validated for Drosophila, it can be used to count automatically cells of comparable properties from other sample types. The parameters can be easily modified by the users to optimise application to non-Drosophila samples. DeadEasy programmes have been developed as freely available ImageJ plug-ins.