Recent developments in high voltage electrical comminution research and its potential applications in the mineral industry

In the current energy-sensitive world, sustainable development in the mineral industry will require new, better and more efficient processes. Novel comminution methods, which offer the prospect of achieving the required outcomes of size reduction and mineral liberation at lower energy consumption, are continually being sought. In the past five years, extensive research using high voltage pulse electrical comminution technology has been carried out at the Julius Kruttschnitt Mineral Research Centre (JKMRC), in collaboration with seiFrag AG. The major outcome of this research is the development of the concept of pre-weakening ore particles by electrical comminution procedures to reduce the energy consumption in the downstream grinding circuit. The research has also verified the preferential liberation of valuable minerals by electrical comminution. Given the advantages, several potential applications of electrical comminution in the mineral industry are proposed, including AG/SAG mill feed pre-weakening, pebble treatment, ball mill feed pre-weakening, early recovery of the liberated valuable minerals, crack/micro crack generation for improved leaching, and smelter slag treatment. For the mineral industry to utilize electrical comminution, two emerging issues identified from the research need to be address. They are the energy consumption by electrical comminution in the locked cycle treatment and the facilities scale up necessary to move this technology from the laboratory to the plant

Additional file 1: Table S1. of Case report of homozygous deletion involving the first coding exons of GCNT2 isoforms A and B and part of the upstream region of TFAP2A in congenital cataract

Summary of PCR/qPCR reactions and copy number status in the affected family. (DOCX 21 kb

Exonic structure, genomic context and multiple species alignment of B3GLCT/b3glct.

<p>(A) The two zebrafish orthologs of B3GLCT show overall similar exonic arrangement. The number of each exon is located within each box and the size of the exon (in base pairs) is shown above each exon. The 5’ and 3’ UTRs are indicated preceding the first ATG and following the stop codon (TAA/TAG). White indicates the N-terminal signal sequence, light grey indicates the stem region and dark grey indicates the catalytic domain. The vertical black bar in exon 12 of each gene indicates the location of nucleotides encoding for the catalytic tri-aspartic acid residues. Horizontal lines underneath the zebrafish genes indicate previously annotated sequence and sequence identified in this study. (B) Schematic of genomic context for B3GLCT/b3glct. (C) Multiple species alignment of B3GLCT orthologs from human (NP_919299), mouse (NP_001074673), Xenopus (NP_001072551), and zebrafish. Blue bar indicates signal peptide, green indicates stem region and orange indicates catalytic core. Grey shading of amino acids indicates conservation. The DxD motif is boxed in red.</p

Summary of differentially regulated genes implicated in ER quality control, unfolded protein response or cell survival.

<p>Summary of differentially regulated genes implicated in ER quality control, unfolded protein response or cell survival.</p

Functional characterization of zebrafish orthologs of the human Beta 3-Glucosyltransferase <i>B3GLCT</i> gene mutated in Peters Plus Syndrome

<div><p>Peters Plus Syndrome (PPS) is a rare autosomal recessive disease characterized by ocular defects, short stature, brachydactyly, characteristic facial features, developmental delay and other highly variable systemic defects. Classic PPS is caused by loss-of-function mutations in the <i>B3GLCT</i> gene encoding for a β3-glucosyltransferase that catalyzes the attachment of glucose via a β1–3 glycosidic linkage to <i>O</i>-linked fucose on thrombospondin type 1 repeats (TSRs). B3GLCT was shown to participate in a non-canonical ER quality control mechanism; however, the exact molecular processes affected in PPS are not well understood. Here we report the identification and characterization of two zebrafish orthologs of the human <i>B3GLCT</i> gene, <i>b3glcta</i> and <i>b3glctb</i>. The <i>b3glcta</i> and <i>b3glctb</i> genes encode for 496-aa and 493-aa proteins with 65% and 57% identity to human B3GLCT, respectively. Expression studies demonstrate that both orthologs are widely expressed with strong presence in embryonic tissues affected in PPS. <i>In vitro</i> glucosylation assays demonstrated that extracts from wildtype embryos contain active b3glct enzyme capable of transferring glucose from UDP-glucose to an <i>O</i>-fucosylated TSR, indicating functional conservation with human B3GLCT. To determine the developmental role of the zebrafish genes, single and double <i>b3glct</i> knockouts were generated using TALEN-induced genome editing. Extracts from double homozygous <i>b3glct</i>^<i>-/-</i> embryos demonstrated complete loss of <i>in vitro</i> b3glct activity. Surprisingly, <i>b3glct</i>^<i>-/-</i> homozygous fish developed normally. Transcriptome analyses of head and trunk tissues of <i>b3glct</i>^<i>-/-</i> 24-hpf embryos identified 483 shared differentially regulated transcripts that may be involved in compensation for b3glct function in these embryos. The presented data show that both sequence and function of <i>B3GLCT/b3glct</i> genes is conserved in vertebrates. At the same time, complete <i>b3glct</i> deficiency in zebrafish appears to be inconsequential and possibly compensated for by a yet unknown mechanism.</p></div

Embryonic expression of zebrafish <i>b3glct</i> genes.

<p>(A) RT-PCR analysis of <i>b3glct</i> expression demonstrates robust expression of both <i>b3glcta</i> (left panel) and <i>b3glctb</i> (middle panel) at different stages of development in whole embryos as well as various embryonic tissues at 48-hpf (right panel). Controls included <i>pitx2c</i> as negative control for 0-hpf, <i>rhodopsin</i> as negative control for the lens, <i>beta-actin</i> as positive control for all tissues and H₂O as negative contamination control for all reactions. (B) In-situ hybridization analysis of <i>b3glcta</i> and <i>b3glctb</i> expression demonstrates broad expression in 24-120-hpf embryos with enrichment in the developing eyes, fins, brain, craniofacial region and somites. aer–apical ectodermal ridge, ase–anterior segment of the eye, b–brain, cmz–ciliary marginal zone, crc–craniofacial cartilage, e–eye, f–fins, h–heart, le–lens, sm–skeletal muscles.</p

Metabolic Alterations Caused by Simultaneous Loss of HK2 and PKM2 Leads to Photoreceptor Dysfunction and Degeneration

HK2 and PKM2 are two main regulators of aerobic glycolysis. Photoreceptors (PRs) use aerobic glycolysis to produce the biomass necessary for the daily renewal of their outer segments. Previous work has shown that HK2 and PKM2 are important for the normal function and long-term survival of PRs but are dispensable for PR maturation, and their individual loss has opposing effects on PR survival during acute nutrient deprivation. We generated double conditional (dcKO) mice lacking HK2 and PKM2 expression in rod PRs. Western blotting, immunofluorescence, optical coherence tomography, and electroretinography were used to characterize the phenotype of dcKO animals. Targeted and stable isotope tracing metabolomics, qRT-PCR, and retinal oxygen consumption were performed. We show that dcKO animals displayed early shortening of PR inner/outer segments, followed by loss of PRs with aging, much more rapidly than either knockout alone without functional loss as measured by ERG. Significant alterations to central glucose metabolism were observed without any apparent changes to mitochondrial function, prior to PR degeneration. Finally, PR survival following experimental retinal detachment was unchanged in dcKO animals as compared to wild-type animals. These data suggest that HK2 and PKM2 have differing roles in promoting PR neuroprotection and identifying them has important implications for developing therapeutic options for combating PR loss during retinal disease

Race- and Sex-Related Differences in Retinal Thickness and Foveal Pit Morphology

This study provides key insight into the underlying mechanism behind the reported race- and sex-related differences in retinal thickness. Variation in foveal pit morphology is shown to underlie apparent racial differences in central retinal thickness

Mutations of conserved non-coding elements of PITX2 in patients with ocular dysgenesis and developmental glaucoma.

Mutations in FOXC1 and PITX2 constitute the most common causes of ocular anterior segment dysgenesis (ASD), and confer a high risk for secondary glaucoma. The genetic causes underlying ASD in approximately half of patients remain unknown, despite many of them being screened by whole exome sequencing. Here, we performed whole genome sequencing on DNA from two affected individuals from a family with dominantly inherited ASD and glaucoma to identify a 748-kb deletion in a gene desert that contains conserved putative PITX2 regulatory elements. We used CRISPR/Cas9 to delete the orthologous region in zebrafish in order to test the pathogenicity of this structural variant. Deletion in zebrafish reduced pitx2 expression during development and resulted in shallow anterior chambers. We screened additional patients for copy number variation of the putative regulatory elements and found an overlapping deletion in a second family and in a potentially-ancestrally-related index patient with ASD and glaucoma. These data suggest that mutations affecting conserved non-coding elements of PITX2 may constitute an important class of mutations in patients with ASD for whom the molecular cause of their disease have not yet been identified. Improved functional annotation of the human genome and transition to sequencing of patient genomes instead of exomes will be required before the magnitude of this class of mutations is fully understood