ANTI-CORROSION COATING OF MILD STEEL USING TERNARY Zn-ZnO-Y2O3 ELECTRO-DEPOSITON

Mild steel has found many engineering applications due to its great formability, availability, low cost and good mechanical properties among others. However its functionality and durability is subject of concern due to corrosion deterioration. Based on these, Yttria is selected as reinforcing particles using electroplating process to enhance the corrosion and wear behaviors. Bath formulation of Zinc- Yttria was prepared at moderated temperature and pH, to coat the sample. Corrosion and wear behaviour were analyzed using electrochemical potentiostat and abrasive test rig. The composition and microstructure of coated samples were investigated using standard method. The microstructure of the deposited sample obtained at 10 % Yttria, revealed fine-grains deposit of the Yttria on the mild steel surface. The results showed that adding of Yttria particles, improved wear behaviour and corrosion resistance in sodium chloride solution. Microhardness of the coated samples showed increases hardness values before and after heat treatment. This work established that elecrodeposition of mild steel with Yttria is promising in increasing the wear and corrosion resistanc

Details of active site, dimeric assembly, and sequence conservation of PduL.

<p>(<b>a</b>,<b>b</b>) Proposed active site of PduL with relevant residues shown as sticks in atom coloring (nitrogen blue, oxygen red, sulfur yellow), zinc as grey colored spheres and coordinating ordered water molecules in red. Distances between atom centers are indicated in Å. (<b>a</b>) Coenzyme A containing, (<b>b</b>) phosphate-bound structure. (<b>c</b>) View of the dimer in the asymmetric unit from the side, domains 1 and 2 colored as in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002399#pbio.1002399.g002" target="_blank">Fig 2</a> and the two chains differentiated by blue/red versus slate/firebrick. The bottom panel shows a top view down the 2-fold axis as indicated by the arrow in the top panel. The asterisk and double arrow marks the location of the π–π interaction between F116 and the CoA base of the other dimer chain. (<b>d</b>) Surface representation of the structure with indicated conservation (red: high, white: intermediate, yellow: low).</p

Structural overview of <i>R</i>. <i>palustris</i> PduL from the <i>grm3</i> locus.

<p>(<b>a</b>) Primary and secondary structure of rPduL (tubes represent α-helices, arrows β-sheets and dashed line residues disordered in the structure. Blocks of ten residues are shaded alternatively black/dark gray. The first 33 amino acids are present only in the wildtype construct and contains the predicted EP alpha helix, α0); the truncated rPduLΔEP that was crystallized begins with M-G-V. Coloring is according to structural domains (domain 1 D36-N46/Q155-C224, blue; loop insertion G61-E81, grey; domain 2 R47-F60/E82-A154, red). Metal coordination residues are highlighted in light blue and CoA contacting residues in magenta, residues contacting the CoA of the other chain are also outlined. (<b>b</b>) Cartoon representation of the structure colored by domains and including secondary structure numbering. The N-and C-termini are in close proximity. Coenzyme A is shown in magenta sticks and Zinc (grey) as spheres.</p

Primary structure conservation of the PduL protein family.

<p>Sequence logo calculated from the multiple sequence alignment of PduL homologs (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002399#sec012" target="_blank">Materials and Methods</a>), but not including putative EP sequences. Residues 100% conserved across all PduL homologs in our dataset are noted with an asterisk, and residues conserved in over 90% of sequences are noted with a colon. The sequences aligning to the PF06130 domain (determined by BLAST) are highlighted in red and blue. The position numbers shown correspond to the residue numbering of rPduL; note that some positions in the logo represent gaps in the rPduL sequence.</p

Size exclusion chromatography of PduL homologs.

<p>(<b>a</b>)–(<b>c</b>): Chromatograms of sPduL (<b>a</b>), rPduL (<b>b</b>), and pPduL (<b>c</b>) with (orange) or without (blue) the predicted EP, post-nickel affinity purification, applied over a preparative size exclusion column (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002399#sec012" target="_blank">Materials and Methods</a>). (<b>d</b>)–(<b>f</b>): Chromatograms of sPduL (<b>d</b>), rPduL (<b>e</b>), and pPduL (<b>f</b>) post-preparative size exclusion chromatography with different size fractions separated, applied over an analytical size exclusion column (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002399#sec012" target="_blank">Materials and Methods</a>). All chromatograms are cropped to show only the linear range of separation based on standard runs, shown in black squares with a dashed linear trend line. All <i>y</i>-axes are arbitrary absorbance units except the right-hand axes for panels (<b>a</b>) and (<b>d</b>), which is the log₁₀(molecular weight) of the standards.</p

Definitions of terms and counts for locus and genome categories analyzed using LoClass.

<p>Definitions of terms and counts for locus and genome categories analyzed using LoClass.</p

A Taxonomy of Bacterial Microcompartment Loci Constructed by a Novel Scoring Method

<div><p>Bacterial microcompartments (BMCs) are proteinaceous organelles involved in both autotrophic and heterotrophic metabolism. All BMCs share homologous shell proteins but differ in their complement of enzymes; these are typically encoded adjacent to shell protein genes in genetic loci, or operons. To enable the identification and prediction of functional (sub)types of BMCs, we developed LoClass, an algorithm that finds putative BMC loci and inventories, weights, and compares their constituent pfam domains to construct a locus similarity network and predict locus (sub)types. In addition to using LoClass to analyze sequences in the Non-redundant Protein Database, we compared predicted BMC loci found in seven candidate bacterial phyla (six from single-cell genomic studies) to the LoClass taxonomy. Together, these analyses resulted in the identification of 23 different types of BMCs encoded in 30 distinct locus (sub)types found in 23 bacterial phyla. These include the two carboxysome types and a divergent set of metabolosomes, BMCs that share a common catalytic core and process distinct substrates via specific signature enzymes. Furthermore, many Candidate BMCs were found that lack one or more core metabolosome components, including one that is predicted to represent an entirely new paradigm for BMC-associated metabolism, joining the carboxysome and metabolosome. By placing these results in a phylogenetic context, we provide a framework for understanding the horizontal transfer of these loci, a starting point for studies aimed at understanding the evolution of BMCs. This comprehensive taxonomy of BMC loci, based on their constituent protein domains, foregrounds the functional diversity of BMCs and provides a reference for interpreting the role of BMC gene clusters encoded in isolate, single cell, and metagenomic data. Many loci encode ancillary functions such as transporters or genes for cofactor assembly; this expanded vocabulary of BMC-related functions should be useful for design of genetic modules for introducing BMCs in bioengineering applications.</p></div

Similarity network of bacterial microcompartment loci.

<p>Nodes represent all Candidate BMC Loci and satellite-like loci analyzed using LoClass. The length of any given edge between two nodes is proportional to the pairwise locus similarity score as generated using the LoClass method. The locus similarity network was clustered using MCL at a score cut-off of 3 and inflation value of 2, resulting in 10 different clusters. Node sizes are proportional to the number of genes in the envelope, the maximal region in the locus bounded by BMC shell protein genes. Node colors and shapes correspond to the locus (sub)type as predicted by our analysis (see key). The white circle in Cluster 1 indicates a locus in a synthetic genome not included in our analysis <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003898#pcbi.1003898-Itaya1" target="_blank">[121]</a>.</p

Simplified workflow of LoClass for locus similarity network generation.

<p>(A) After genes encoding BMC shell proteins (PF00936, dark blue; PF03319, yellow) are identified using <i>hmmsearch</i>, their position on the chromosome is determined. The region 10 kb upstream and downstream of each PF00936 and PF03319 domain is considered a Prospective BMC Locus (pale blue). The envelope (blue) is defined as the maximal portion of the Prospective BMC Locus bounded by BMC shell protein genes. (B) Where Prospective BMC Loci overlap, they are merged into one Prospective Locus. (C) All non-shell protein genes in the Prospective Locus are searched against Pfam <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003898#pcbi.1003898-Punta1" target="_blank">[12]</a>. Pfam hits are represented by colored regions of the genes. Genes without pfams hits (white) are not considered. (D) Loci are represented by their pfam set, excluding genes containing PF00936 and PF03319 domains. Pfams, represented by colored rectangles, are weighted based on their relative distance from the envelope. This distance weight is represented by the darkness of the background behind the rectangles, where a black background corresponds to a pfam found inside the envelope with a weight of 1, and where a light grey background corresponds to a pfam separated from the envelope by at least four open reading frames with a weight of 0.6. <i>P_I</i> is the set of pfams found in Locus I, while <i>P_J</i> represents the set of pfams found in a different Locus J (not shown). (E) By comparing the sets of pfams <i>P_I</i> and <i>P_J</i>, we determine the set <i>C_I,J</i> of common pfams to both loci and the two sets <i>D_I,J</i> and <i>D_J,I</i> of pfams unique to Locus I and Locus J, respectively. These three sets, along with the distance weight and the other weights (<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003898#s2" target="_blank">Materials and Methods</a>) are then used to calculate the locus similarity score between these two loci.</p

Representative BMC Loci.

<p>Cartoon representation of the most highly conserved contiguous region of the Representative Loci, in order of appearance in the text. Where a (sub)type is dominated by many highly syntenic examples from one or two species, locus bounds were chosen based on conservation across all species in the (sub)type. Locus statistics are represented in the “S (L/G)” column: “S” represents number of species that contain the locus, “L” represents the number of loci, and “G” represents the number of genomes that encode the locus. Genes are color-coded according to their annotation: blue, BMC-H; cyan, BMC-T; yellow, BMC-P; red, aldehyde dehydrogenase; green, iron-containing alcohol dehydrogenase; green diagonal hash, other putative alcohol dehydrogenases; solid pink, <i>pduL</i>-type phosphotransacylase; pink diagonal hash, <i>pta</i>-type phosphotransacylase; purple diagonal hash, RuBisCO large and small subunits; purple vertical hash, ethanolamine ammonia lyase subunits; purple crosshatch, propanediol dehydratase subunits; purple horizontal hash, glycyl radical enzyme and activase; dotted purple, aldolase; solid purple, aminotransferase; brown, regulatory element including two-component signaling elements; orange, transporter; teal, actin/<i>parA</i>/<i>pduV</i>/<i>eutP</i>-like. Genes colored gray indicate that the gene is present in over 50% of members in the locus (sub)type described (e.g. GRM1), and are in over 50% of members of at least one other locus (sub)type (e.g. found in GRM1 and GRM3). Genes colored black indicate that the gene is present in over 50% of members in the locus (sub)type described and not present in over 50% of members of any other locus (sub)type. Genes colored white are those that are present in the Representative Locus but are not present in over 50% of members of that locus (sub)type. Representative Loci are highlighted in yellow in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003898#pcbi.1003898.s001" target="_blank">Dataset S1</a>.</p