Liquid facets-Related (lqfR) Is Required for Egg Chamber Morphogenesis during Drosophila Oogenesis

Clathrin interactor 1 [CLINT1] (also called enthoprotin/EpsinR) is an Epsin N-terminal homology (ENTH) domain-containing adaptor protein that functions in anterograde and retrograde clathrin-mediated trafficking between the trans-Golgi network and the endosome. Removal of both Saccharomyces cerevisiae homologs, Ent3p and Ent5p, result in yeast that are viable, but that display a cold-sensitive growth phenotype and mistrafficking of various vacuolar proteins. Similarly, either knock-down or overexpression of vertebrate CLINT1 in cell culture causes mistrafficking of proteins. Here, we have characterized Drosophila CLINT1, liquid-facets Related (lqfR). LqfR is ubiquitously expressed throughout development and is localized to the Golgi and endosome. Strong hypomorphic mutants generated by imprecise P-element excision exhibit extra macrochaetae, rough eyes and are female sterile. Although essentially no eggs are laid, the ovaries do contain late-stage egg chambers that exhibit abnormal morphology. Germline clones reveal that LqfR expression in the somatic follicle cells is sufficient to rescue the oogenesis defects. Clones of mutant lqfR follicle cells have a decreased cell size consistent with a downregulation of Akt1. We find that while total Akt1 levels are increased there is also a significant decrease in activated phosphorylated Akt1. Taken together, these results show that LqfR function is required to regulate follicle cell size and signaling during Drosophila oogenesis

Chemically modified carbon nanotubes for use in electroanalysis

A review. The discovery of carbon nanotubes has had a profound impact on many areas of science and technol., not least that of electroanal. The properties and applications of carbon nanotubes themselves were well reviewed in the literature and a no. of reviews with an electrochem. emphasis were published. However, the modification of carbon nanotubes has recently been the focus of much research, primarily to improve their soly. in various solvents. Yet modified carbon nanotube electrodes also allow the electrochemist to tailor the properties of the carbon nanotubes, or the electrode surface to impart desired properties such as enhanced sensing capabilities. In this review it is attempted to comprehensively cover the different chem. and electrochem. modification strategies and research carried out using modified carbon nanotubes for electroanal. and bioanal. applications. Furthermore it is also discussed the use of modified carbon nanotubes in electrocatalysis and biocatalysis from an anal. aspect, as well as seeking to dispel some of the myths surrounding the electrocatalytic properties of carbon nanotubes. [on SciFinder(R)

X-ray photoelectron spectroscopy studies of graphite powder and multiwalled carbon nanotubes covalently modified with Fast Black K: evidence for a chemical release mechanism via electrochemical reduction

The development of new materials from which to construct controlled chem.-release systems was an active area of research for the past 4 decades. Using XPS graphite powder and multiwalled C nanotubes (MWCNTs) covalently derivatized with 2,5-dimethoxy-4-[4-(nitrophenyl)azo]benzenediazonium chloride (FBK) or a deriv. of FBK are important new micro and nano-scale materials for use as voltammetrically controlled chem.-release reagents in applications where the small size of the material is advantageous. By examg. the N1s and O1s regions of the XPS spectra the authors can identify functionalities within the FBK moiety as well as hydroxyl, quinonyl and carboxylic acid functional groups present on the C surface. Comparison of the XPS spectra of the FBK derivatized C (FBK carbon) and FBK derivatized MWCNTs (FBK-MWCNTs) before and after electrochem. redn. reveals that cleavage of the azo-linkage within the FBK moiety occurs upon redn. in aq. soln. The voltammetric cleavage of the azo-linkage induces chem. release of 1,4-phenylenediamine from the C surface, demonstrating the proof of concept for these novel materials. It is envisaged that derivs. of these materials could be used in vivo in a wide range of areas including medical diagnosis and targeted drug-delivery systems as well as in in vitro applications such as anal. chem., sensor technol. and industrial process monitoring and control. [on SciFinder(R)

Derivatized carbon powder electrodes: reagentless pH sensors

The authors derivatize C powder with anthracene, azobenzene, diphenylamine, 9,10-diphenylanthracene, methylene blue, 3-nitrofluoranthene, 6-nitrochrysene, 9-nitroanthracene, 9,10-phenanthraquinone (PAQ), thionin, and fast black K (2,5-dimethoxy-4-[(4-nitrophenyl)azo]benzenediazonium chloride) and sep. immobilize the resulting material onto a bppg electrode. The authors use cyclic voltammetry (CV) to demonstrate that the obsd. voltammetric response for each derivatized C is consistent with that of an immobilized species. Further, the authors use CV and square wave voltammetry (SWV) to study the effect of pH on the peak potentials of each compd. studied over the range pH 1-12 and at elevated temps. up to 70° to demonstrate the versatility of derivatized C electrodes as reagentless pH sensors. [on SciFinder(R)

Multiwalled carbon nanotubes with molybdenum dioxide nanoplugs - new chemical nanoarchitectures by electrochemical modification

The electrochem. deposition of MoO2 at edge-plane-like sites along the surface of MWCNTs produces nanoplugs of MoO2 at the ends of the tubes, which are the regions of greatest electrochem. activity. It also speculates that it may be possible to form nanorings of MoO2 around the circumference of the nanotube. It is envisaged that, as nanotechnol. progresses, this rapid and simple method of forming nanoplugs at the ends of CNTs may be used in the fabrication of nanoelectronic circuitry. MoO2 can be easily reduced to Mo metal by heating to around 500° under a flow of hydrogen gas as the MWCNTs can withstand temps. up to around 700°. The Mo metal at the ends of the CNTs could then be used to form well-defined elec. contacts between CNTs. [on SciFinder(R)