Factors Necessary (factor + necessary)

Distribution by Scientific Domains


Selected Abstracts


FlbC is a putative nuclear C2H2 transcription factor regulating development in Aspergillus nidulans

MOLECULAR MICROBIOLOGY, Issue 5 2010
Nak-Jung Kwon
Summary Asexual development (conidiation) in Aspergillus is governed by multiple regulators. Here, we characterize the upstream developmental activator FlbC in Aspergillus nidulans. flbC mRNA is detectable throughout the life cycle, at relatively high levels during vegetative growth, early asexual and late sexual developmental phases. The deletion of flbC causes a delay/reduction in conidiation, brlA and vosA expression, and conidial germination. While overexpression of flbC (OEflbC) does not elaborate conidiophores, it inhibits hyphal growth and activates expression of brlA, abaA and vosA, but not wetA. FlbC is conserved in filamentous Ascomycetes containing two C2H2 zinc fingers at the C-terminus and a putative activation domain at the N-terminus. FlbC localizes in the nuclei of both hyphae and developmental cells. Localization and expression of FlbC are not affected by the absence of FlbB or FlbE, and vice versa. Importantly, overexpression of flbC causes growth inhibition and activation of abaA and vosA in the absence of brlA and abaA respectively. In vitro DNA-binding assay reveals that FlbC binds to the brlA, abaA and vosA, but not the wetA, promoters. In summary, FlbC is a putative nuclear transcription factor necessary for proper activation of conidiation, and its balanced activity is crucial for governing growth and development in A. nidulans. [source]


ESX-1-dependent cytolysis in lysosome secretion and inflammasome activation during mycobacterial infection

CELLULAR MICROBIOLOGY, Issue 9 2008
Ingrid C. Koo
Summary Exocytosis of lysosomes from macrophages has been described as a response to microbial cytotoxins and haemolysins, as well as for releasing pro-inflammatory cytokines interleukin (IL)-1, and IL-18 during inflammasome activation. The mycobacterial ESX-1 secretion system, encoded in part by the Region of Difference-1, is a virulence factor necessary for phagosome escape and host cell lysis by a contact-dependent haemolysin in Mycobacterium marinum. Here we show that ESX-1 from M. marinum and M. tuberculosis is required for Ca2+ -dependent induction of lysosome secretion from macrophages. Mycobacteria-induced lysosome secretion was concurrent to release of IL-1, and IL-18, dependent on phagocytosis of bacteria containing ESX-1. Synthesis but not release of IL-1, and IL-18 occurred in response to dead bacilli and bacteria lacking ESX-1, indicating that only cytokine release was regulated by ESX-1. Release of these cytokines and exocytosis of lysosomes were independent of intracellular mycobacterial growth, yet correlated with mycobacteria-encoded haemolytic activity, demonstrating a parallel pathway for the two responses. We further identified inflammasome components caspase-1, ASC and NALP3, but not Ipaf, required for release of IL-1, and IL-18. Collectively, these results reveal a role for ESX-1 in triggering secretion of lysosomes, as well as release of IL-1, and IL-18 during mycobacteria infection. [source]


On the Possibility of "International Community"

INTERNATIONAL STUDIES REVIEW, Issue 1 2009
David C. Ellis
The term "international community" has recently become commonplace in leaders' and academics' discourse and the subject of some analysis. While scholars have begun to explore its usage, there has not yet been a modern theoretical evaluation of the prerequisites for creating an international community. This article conducts a theoretical analysis on the types of international communities that can be generated in international politics and the structural factors necessary for their manifestation. It continues by investigating the possibility of forming a unitary actor, called the "International Community," tasked with resolving global commons issues through an international organization, such as the United Nations. The article concludes by arguing that the conditions do not yet exist for a meaningful "International Community." [source]


Inorganic phosphate as a signaling molecule in osteoblast differentiation,

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2003
George R. Beck Jr.
Abstract The spatial and temporal coordination of the many events required for osteogenic cells to create a mineralized matrix are only partially understood. The complexity of this process, and the nature of the final product, demand that these cells have mechanisms to carefully monitor events in the extracellular environment and have the ability to respond through cellular and molecular changes. The generation of inorganic phosphate during the process of differentiation may be one such signal. In addition to the requirement of inorganic phosphate as a component of hydroxyapatite mineral, Ca10(PO4)6(OH)2, a number of studies have also suggested it is required in the events preceding mineralization. However, contrasting results, physiological relevance, and the lack of a clear mechanism(s) have created some debate as to the significance of elevated phosphate in the differentiation process. More recently, a number of studies have begun to shed light on possible cellular and molecular consequences of elevated intracellular inorganic phosphate. These results suggest a model in which the generation of inorganic phosphate during osteoblast differentiation may in and of itself represent a signal capable of facilitating the temporal coordination of expression and regulation of multiple factors necessary for mineralization. The regulation of protein function and gene expression by elevated inorganic phosphate during osteoblast differentiation may represent a mechanism by which mineralizing cells monitor and respond to the changing extracellular environment. J. Cell. Biochem. 90: 234,243, 2003. Published 2003 Wiley-Liss, Inc. [source]


Nonprofit mergers: Assessing the motivations and means

JOURNAL OF LEADERSHIP STUDIES, Issue 4 2010
Julie Pietroburgo
As nonprofit organizations seek to remain viable in an increasingly competitive environment, merger is an attractive (albeit complicated) option. This case study of the largest nonprofit association merger in U.S. history, involving three bowling associations, demonstrates the critical role of leadership in consummating a merger. The case illustrates a number of factors necessary to merger success: existence of a catalyst leader and a nucleus of like-minded individuals who can serve as the impetus for change, sufficient time to accommodate the psychological and practical aspects of merging, opportunities for building social capital among the people involved in the merger, and preservation of cultural remnants that are carried over from the predecessor organizations to the newly merged entity. [source]


Connective Tissue Growth Factor Promotes Fibrosis Downstream of TGF, and IL-6 in Chronic Cardiac Allograft Rejection

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2010
A. J. Booth
Cardiac transplantation is an effective treatment for multiple types of heart failure refractive to therapy. Although immunosuppressive therapeutics have increased survival rates within the first year posttransplant, chronic rejection (CR) remains a significant barrier to long-term graft survival. Indicators of CR include patchy interstitial fibrosis, vascular occlusion and progressive loss of graft function. Multiple factors have been implicated in the onset and progression of CR, including TGF,, IL-6 and connective tissue growth factor (CTGF). While associated with CR, the role of CTGF in CR and the factors necessary for CTGF induction in vivo are not understood. To this end, we utilized forced expression and neutralizing antibody approaches. Transduction of allografts with CTGF significantly increased fibrotic tissue development, though not to levels observed with TGF, transduction. Further, intragraft CTGF expression was inhibited by IL-6 neutralization whereas TGF, expression remained unchanged, indicating that IL-6 effects may potentiate TGF,-mediated induction of CTGF. Finally, neutralizing CTGF significantly reduced graft fibrosis without reducing TGF, and IL-6 expression levels. These findings indicate that CTGF functions as a downstream mediator of fibrosis in CR, and that CTGF neutralization may ameliorate fibrosis and hypertrophy associated with CR. [source]


Photolithographic Patterning of C2C12 Myotubes using Vitronectin as Growth Substrate in Serum-Free Medium

BIOTECHNOLOGY PROGRESS, Issue 1 2007
Peter Molnar
The C2C12 cell line is frequently used as a model of skeletal muscle differentiation. In our serum-free defined culture system, differentiation of C2C12 cells into myotubes required surface-bound signals such as substrate-adsorbed vitronectin or laminin. On the basis of this substrate requirement of myotube formation, we developed a photolithography-based method to pattern C2C12 myotubes, where myotubes formed exclusively on vitronectin surface patterns. We have determined that the optimal line width to form single myotubes is approximately 30 ,m. To illustrate a possible application of this method, we patterned myotubes on the top of commercial substrate-embedded microelectrodes. In contrast to previous experiments where cell patterning was achieved by selective attachment of the cells to patterned surfaces in a medium that contained all of the factors necessary for differentiation, this study illustrates that surface patterning of a signaling molecule, which is essential for skeletal muscle differentiation in a defined system, can result in the formation of aligned myotubes on the patterns. This technique is being developed for applications in cell biology, tissue engineering, and robotics. [source]