Charge-storage mechanism of free-standing MoS 2 /r-GO (r-GO = reduced graphene oxide) hybrid nanoflakes on molybdenum (Mo) foil in Na 2 SO 4 solution is elucidated for realizing a high-performance asymmetric supercapacitor (ASC). Thiourea that acts primarily as sulfur source also helps intercalating ammonium ions, which along with r-GO facilitate in situ exfoliation of MoS 2 , producing hierarchical MoS 2 with expanded interlayer spacing. This interlayer expansion in MoS 2 facilitates Na + -ions intercalation/deintercalation and ensures enhanced capacitance, rate capability, and cycling stability of the capacitor . Besides exhibiting attractive energy-cum-power traits, the 2 V MoS 2 /r-GO//Fe 2 O 3 /MnO 2 ASC shows compelling cycling performance for over 20 000 cycles in an aqueous electrolyte.

SummaryThe synthesis of 5-aminolevulinic acid (ALA) is the rate-limiting step for the formation of all plant tetrapyrroles, including chlorophyll and heme, and regulation of ALA synthesis is therefore critical to plant development. Glutamyl-tRNA reductase (GluTR) is the ®rst committed enzyme of this pathway and is encoded by a small family of nuclear HEMA genes. Here, we have used transgenic Arabidopsis (Arabidopsis thaliana L. Col) lines expressing chimeric HEMA1 promoter:gusA fusion genes, combined with RNA gel blot analyses, to characterise the light-mediated regulation of the Arabidopsis HEMA1 gene during de-etiolation. HEMA1 was expressed strongly, but not exclusively, in photosynthetic tissues and was shown to be light regulated at the transcriptional level by the phytochrome family of photoreceptors acting in both the far-red high irradiance and low¯uence response modes. The HEMA2 gene, which is expressed only in roots of seedlings, was not light regulated. Analysis of truncated HEMA1 promoter constructs demonstrated that a ±199/+252 promoter fragment was suf®cient to confer full light-responsiveness to gusA expression. This fragment contained GT-1/I-box and CCA-1 binding sites that are implicated as the light-responsive cis elements. Both the full-length and truncated HEMA1 promoters required the presence of intact chloroplasts for full expression, consistent with previous indications that light and plastid factor signals converge to co-ordinately regulate expression of photosynthesis-related nuclear genes. These results provide the most comprehensive analysis to date of the light-regulation of a tetrapyrrole biosynthetic gene and support a direct link between regulation of HEMA1 transcription and chlorophyll accumulation during seedling de-etiolation.

5-Aminolevulinic acid (ALA) is the universal precursor of tetrapyrroles, such as chlorophyll and heme. The major control of chlorophyll biosynthesis is at the step of ALA formation. In the chloroplasts of plants, as in Escherichia coli, ALA is derived from the glutamate of GIu-tRNA via the two-step C5 pathway. The first enzyme, GIu-tRNA reductase, catalyzes the reduction of GIu-tRNA to glutamate 1-semialdehyde with the release of intact tRNA. The second enzyme, glutamate 1-semialdehyde 2,1-aminomutase, converts glutamate 1-semialdehyde to ALA. To further examine ALA formation in plants, we isolated Arabidopsis genes that encode the enzymes of the C5 pathway via functional complementation of mutations in the corresponding genes of E. coli. The GIu-tRNA reductase gene was designated HEMA and the glutamate 1-semialdehyde 2,l-aminomutase gene, GSA7. Each gene contains two short introns (149 and 241 nucleotides for HEMA, 153 and 86 nucleotides for GSA7). The deduced amino acid sequence of the HEMA protein predicts a protein of 60 kD with substantial similarity (30 to 47% identity) to sequences derived from the known hemA genes from microorganisms that make ALA by the C5 pathway. Purified Arabidopsis HEMA protein has GIutRNA reductase activity. The GSA7 gene encodes a 50-kD protein whose deduced amino acid sequence shows extensive homology (55 to 78% identity) with glutamate 1-semialdehyde 2,l-aminomutase proteins from other species. RNA gel blot analyses indicated that transcripts for both genes are found in root, leaf, stem, and flower tissues and that their levels are dramatically elevated by light. Thus, light may regulate ALA, and hence chlorophyll formation, by exerting coordinated transcriptional control over both enzymes of the C5 pathway.

Background: Chediak-Higashi syndrome (CHS) is an inherited immunodeficiency disease characterized by giant lysosomes and impaired leukocyte degranulation. CHS results from mutations in the lysosomal trafficking regulator (LYST) gene, which encodes a 425-kD cytoplasmic protein of unknown function. The goal of this study was to identify proteins that interact with LYST as a first step in understanding how LYST modulates lysosomal exocytosis. Materials and Methods: Fourteen cDNA fragments, covering the entire coding domain of LYST, were used as baits to screen five human cDNA libraries by a yeast twohybrid method, modified to allow screening in the activation and the binding domain, three selectable markers, and more stringent confirmation procedures. Five of the interactions were confirmed by an in vitro binding assay.

5-Aminolevulinic acid (ALA) is a precursor in the biosynthesis of tetrapyrroles including chlorophylls and heme. The formation of ALA involves two enzymatic steps which take place in the chloroplast in plants. The first enzyme, glutamyl-tRNA reductase, and the second enzyme, glutamate-1-semialdehyde-2,1-aminomutase, are encoded by the nuclear HEMA and GSA genes, respectively. To assess the significance of the HEMA gene for chlorophyll and heme synthesis, transgenic Arabidopsis plants that expressed antisense HEMA1 mRNA from the constitutive cauliflower mosaic virus 35S promoter were generated. These plants exhibited varying degrees of chlorophyll deficiency, ranging from patchy yellow to total yellow. Analysis indicated that these plants had decreased levels of chlorophyll, non-covalently bound hemes, and ALA; their levels were proportional to the level of glutamyl-tRNA reductase expression and were inversely related to the levels of antisense HEMA transcripts. Plants that lacked chlorophyll failed to survive under normal growth conditions, indicating that HEMA gene expression is essential for growth.