Nitrogen fertilizer unabsorbed by crops eventually discharges into the environment through runoff, leaching and volatilization, resulting in three-dimensional (3D) pollution spanning from underground into space. Here we describe an approach for controlling nitrogen loss, developed using loss control fertilizer (LCF) prepared by adding modified natural nanoclay (attapulgite) to traditional fertilizer. In the aqueous phase, LCF self-assembles to form 3D micro/nano networks via hydrogen bonds and other weak interactions, obtaining a higher nitrogen spatial scale so that it is retained by a soil filtering layer. Thus nitrogen loss is reduced and sufficient nutrition for crops is supplied, while the pollution risk of the fertilizer is substantially lowered. As such, self-fabrication of nano-material was used to manipulate the nitrogen spatial scale, which provides a novel and promising approach for the research and control of the migration of other micro-scaled pollutants in environmental medium.

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Simplicity has made C. elegans pharyngeal development a particularly well-studied subject. Nevertheless, here we add the previously uncharacterized homeobox gene F20D12.6/ceh-19 to the set of transcription factor genes involved. GFP reporter assays revealed that ceh-19 is expressed in three pairs of neurons, the pharyngeal pace-maker neurons MC, the amphid neurons ADF and the phasmid neurons PHA. ceh-19(tm452) mutants are viable and fertile, but grow slightly slower, produce less progeny over a prolonged period, and live longer than the wild type. These phenotypes are likely due to the moderately reduced pharyngeal pumping speed arising from the impairment of MC activity. MC neurons are still born in the ceh-19 mutants but display various morphological defects. ceh-19 expression in MC is completely lost in progeny from animals subject to RNAi for pha-4, which encodes an organ-specifying forkhead transcription factor. CEH-19 is required for the activation in MCs of the excitatory FMRFamide-like neuropeptide-encoding gene flp-2. A regulatory pathway from pha-4 through ceh-19 to flp-2 is thereby defined. The resilience of MC identity in the absence of CEH-19 may reflect the buffering qualities of transcription factor regulatory networks. genesis 51:163–178, 2013. © 2013 Wiley Periodicals, Inc.

Homeobox proteins are critical regulators of developmental gene transcription and cell specification. Many insights into transcriptional regulation have been gained from studies in the nematode Caenorhabditis elegans. We investigated the expression and regulation of the C. elegans homeobox gene ceh-63, which encodes a single-homeodomain transcription factor of 152 amino acids. ceh-63 is expressed in the interneuron DVC in both sexes, from late embryogenesis through adulthood, and two pairs of uterine cells in reproductive hermaphrodites only. A reporter gene fusion, encoding GFP fused to the full-length CEH-63, also drove weak inconsistent expression in additional unidentified cells in the head and tail. A potential ceh-63 null mutant had no obvious abnormalities, except for a possible increase in subtle defects of the DVC axon projection. No behavioural responses were observed upon either laser ablation of DVC or activation of DVC through light stimulation of channelrhodopsin-2 specifically expressed in this neuron. The function of DVC therefore remains enigmatic. A transcriptional regulatory cascade operating in DVC was defined from the LIM-homeodomain protein CEH-14 through CEH-63 to the helix–turn–helix transcription factor MBR-1. Both CEH-14 and CEH-63 individually bound the mbr-1 promoter in a yeast one-hybrid assay. A model is proposed suggesting that CEH-14 activates ceh-63 and then along with CEH-63 co-ordinately activates mbr-1.