bluuebunny/crossref_metadata_2025 huggingface dataset:
Cloning of the gene for the surface array protein of Aeromonas salmonicida and evidence linking loss of expression with genetic deletion
Authors: Belland R J , Trust T J
Published: November 2016

A gene bank of DNA from the fish pathogenic bacterium Aeromonas salmonicida was constructed in the bacteriophage lambda gt11. Phage lambda gt11/10G, a recombinant carrying a 4.0-kilobase fragment of A. salmonicida DNA, was found to express the surface array protein (A protein) in Escherichia coli. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the protein expressed from the cloned gene had a subunit molecular weight of 49,000, which was identical to that of subunits in the native assembled A layer. Genomic Southern analysis showed that the gene coding for this predominant cellular protein was in a single copy on the chromosome and was conserved among a wide range of A. salmonicida strains with different phenotypic characteristics and isolated from diverse geographic locations, fish species, and means of pathogenesis. Results of genomic blotting experiments also showed that loss of expression of the A layer resulting from growth at 30 degrees C was accompanied by genetic rearrangement in which N-terminal sequences of the gene for A protein were lost by deletion.
Antigenic distinctiveness, heterogeneity, and relationships of Methanothrix spp
Authors: Macario A J , Conway de Macario E
Published: November 2016

A detailed immunologic analysis of Methanothrix soehngenii Opfikon (the type species of the genus), Methanothrix sp. strain CALS-1, and Methanothrix concilii GP6 was performed. A variety of poly- and monoclonal antibody probes for a comprehensive panel of reference organisms were used to determine immunogenicity, antigenicity, and relationships. The three organisms are antigenically distinct but interrelated, forming an immunologically cohesive group, weakly related to methanosarcinae. A prominent feature of the organisms was heterogeneity characterized by antigenic diversity and compartmentation, the latter particularly evident in M. soehngenii Opfikon, which was examined more thoroughly. The complexity of the antigenic profile of this strain and the heterogeneity of the group suggest a high degree of phenotypic diversification within the genus.
Isolation and properties of extracellular proteinases from Sporothrix schenckii
Authors: Tsuboi R , Sanada T , Takamori K , Ogawa H
Published: November 2016

Sporothrix schenckii, mainly in the yeast form of the organism, produced extracellular proteinases when cultivated in liquid media containing albumin or collagen as a nitrogen source, but did not do so in brain heart infusion medium. Isolation of two extracellular proteinases from albumin-containing medium was performed by chromatography on DEAE-Sepharose CL-6B and Sephacryl S-200. Proteinase I had a molecular weight of 36,500, an optimal pH at 6.0, and a pI at 4.8. Despite its activities in weakly acidic conditions, proteinase I demonstrated chymotrypsinlike characteristics, these being indicated by strong inhibitory activity by phenylmethylsulfonyl fluoride and chymostatin and good kinetic constants for a synthetic chymotrypsin substrate, Suc-Ala-Ala-Pro-Phe-MCA. Proteinase II had a molecular weight of 39,000, an optimal pH at 3.5, and a pI at 3.8. Proteinase II showed cathepsin D-like characteristics, these being indicated by strong inhibitory activity by pepstatin, an acidic optimal pH, and good kinetic constants for hemoglobin. These two enzymes hydrolyzed natural substrates such as stratum corneum, type I collagen, and elastin although not type IV collagen. Proteinase production and cell growth in collagen-containing medium and the enzymatic digestion of skin constituents by isolated proteinases suggested that these two proteinases cooperatively enable the organism to invade skin and to obtain peptides from insoluble proteins.
5-Fluorouracil-resistant strain of Methanobacterium thermoautotrophicum
Authors: Nagle D P , Teal R , Eisenbraun A
Published: November 2016

Growth of Methanobacterium thermoautotrophicum Marburg is inhibited by the pyrimidine, 5-fluorouracil (FU). It was shown previously that methanogenesis is not inhibited to the same extent as growth. A spontaneously occurring FU-resistant strain (RTAE-1) was isolated from a culture of strain Marburg. The growth of both strains was inhibited by 5-fluorodeoxyuridine but not 5-fluorocytosine, and the wild type was more susceptible to inhibition by 5-azauracil and 6-azauracil than was strain RTAE-1. The cellular targets for the pyrimidine analogs are not known. When the accumulation of 14C-labeled uracil or FU by the two strains was compared, the wild type took up 15-fold more radiolabel per cell than did the FU-resistant strain. In the wild type, radiolabel from uracil was incorporated into the soluble pool, RNA, and DNA. The metabolism of uracil appeared to involve a uracil phosphoribosyltransferase activity. Strain Marburg extracts contained this enzyme, whereas FU-resistant strain RTAE-1 extracts had less than 1/10 as much activity. Although it is possible that a change in permeability to the compounds plays a role in the stable resistance of strain RTAE-1, the fact that it lacks the ability to metabolize pyrimidines to nucleotides is sufficient to account for its phenotype.
Overproduction of Escherichia coli integration host factor, a protein with nonidentical subunits
Authors: Nash H A , Robertson C A , Flamm E , Weisberg R A , Miller H I
Published: November 2016

Integration host factor (IHF) is a small, basic protein that is needed for efficient recombination of bacteriophage lambda, as well as for other host and viral functions. We have constructed strains in which the two subunits of IHF, encoded by the himA and hip genes of Escherichia coli, are expressed under the control of the lambda rho L promoter. Separate overexpression of himA and hip led to the production of unstable and insoluble peptides, respectively. In contrast, the overexpression of both genes conjointly led to the accumulation of large amounts of active IHF. Extracts of such cells provided the starting material for a rapid purification procedure that results in milligram quantities of apparently homogeneous IHF.
Suppression of rpoH (htpR) mutations of Escherichia coli: heat shock response in suhA revertants
Authors: Tobe T , Kusukawa N , Yura T
Published: November 2016

Temperature-resistant pseudorevertants were isolated from rpoH (htpR) mutants of Escherichia coli K-12 that cannot grow at a high temperature owing to a deficiency in sigma 32 required for the induction of heat shock proteins. Among them was a class of revertants carrying a suppressor mutation, designated suhA, that suppressed all the nonsense and missense rpoH mutations tested. suhA is located at 77 min, about 1 min away from rpoH, on the genetic map. In contrast to the rpoH mutants, the suhA revertants that contained both rpoH (nonsense) and suhA mutations were fully or partially proficient in the induction of heat shock proteins upon exposure to a high temperature. Under these conditions, transcription from two heat shock promoters as determined by operon fusion was transiently activated. In one of the rpoH(Am) suhA revertants studied in detail, an increase in temperature caused the synthesis of significant amounts of sigma 32, accompanied by increased stability and accumulation of rpoH mRNAs. On the other hand, the same mutation (suhA6) only weakly suppressed the rpoH deletion mutant; however, two of the major heat shock genes, dnaK and groE, were apparently induced in the absence of sigma 32. Thus, suhA6 seems to bring about the induction of heat shock genes by at least two mechanisms, one increasing the level of sigma 32 synthesis, and the other activating some transcription factor other than sigma 32.
Membrane protein binding to the origin region of Bacillus subtilis
Authors: Laffan J , Firshein W
Published: November 2016

Binding of membrane proteins extracted from Bacillus subtilis to an 11.6-kilobase region containing the origin of replication was examined by Western blotting (protein blotting) procedures. Two adjacent origin probes in the double-stranded form (spanning a length of 4 kilobases) were found to bind very strongly to a 63-kilodalton (kDa) protein in that they resisted dissociation after a high-concentration salt wash. This region encompasses both a site implicated in initiation in vivo and a gene coding for a DNA gyrase subunit (gyrA). In contrast, flanking origin and nonorigin double-stranded probes were dissociated after washing with a high salt concentration. Another protein of 67 kDa bound less intensely to the putative initiation site but not to the gyrA region. All of the origin and nonorigin probes in the double- or single-stranded form were found to bind nonspecifically to a subset of 10 to 12 proteins of 50 to 60 separated by gel electrophoresis after a low-concentration salt wash. They ranged in size from 14 to over 100 kDa (including 63 kDa). However, in contrast to the double-stranded forms, most of the single-stranded probes resisted dissociation from the protein subset after a high-concentration salt wash.
Effects of temperature-sensitive variants of the Bacillus subtilis dnaB gene on the replication of a low-copy-number plasmid
Authors: Watabe K , Forough R
Published: November 2016

The dnaB gene of Bacillus subtilis is involved in the initiation of DNA replication and also in the binding of the chromosomal origin to the bacterial membrane. We studied the effect of temperature-sensitive dnaB mutants (dnaB1 and dnaB19) on the replication and on the DNA-membrane binding of the plasmid pKW1, which was derived from the low-copy-number plasmid pBS2. In the dnaB19 mutant, pKW1 was not able to replicate at the restrictive temperature. In the dnaB1 mutant, however, the dimeric form of pKW1 DNA was preferentially produced as the restrictive temperature, but the replication of the monomeric form was totally blocked. We also examined the effects of the dnaB(Ts) gene on the DNA-membrane binding of both the double-stranded and single-stranded DNA from pKW1. The single-stranded DNA from pKW1 was prepared from the DNA of the phage M13 mp19, which contained the origin of replication of pKW1. In the dnaB1 mutant, pKW1 DNA in both the double-stranded and single-stranded form was released from the membrane at the restrictive temperature. On the other hand, in the dnaB19 mutant, only double-stranded DNA, and not single-stranded DNA, was released from the membrane at the restrictive temperature. These results suggest that the product of the dnaB gene has at least two domains which influence the replication of DNA and the binding of DNA to the cell membrane in separate ways.
Nucleotide sequence of the glucoamylase gene GLU1 in the yeast Saccharomycopsis fibuligera
Authors: Itoh T , Ohtsuki I , Yamashita I , Fukui S
Published: November 2016

The complete nucleotide sequence of the glucoamylase gene GLU1 from the yeast Saccharomycopsis fibuligera has been determined. The GLU1 DNA hybridized to a polyadenylated RNA of 2.1 kilobases. A single open reading frame codes for a 519-amino-acid protein which contains four potential N-glycosylation sites. The putative precursor begins with a hydrophobic segment that presumably acts as a signal sequence for secretion. Glucoamylase was purified from a culture fluid of the yeast Saccharomyces cerevisiae which had been transformed with a plasmid carrying GLU1. The molecular weight of the protein was 57,000 by both gel filtration and acrylamide gel electrophoresis. The protein was glycosylated with asparagine-linked glycosides whose molecular weight was 2,000. The amino-terminal sequence of the protein began from the 28th amino acid residue from the first methionine of the putative precursor. The amino acid composition of the purified protein matched the predicted amino acid composition. These results confirmed that GLU1 encodes glucoamylase. A comparison of the amino acid sequence of glucoamylases from several fungi and yeast shows five highly conserved regions. One homology region is absent from the yeast enzyme and so may not be essential to glucoamylase function.
Genetic analysis of agrocin 84 production and immunity in Agrobacterium spp
Authors: Ryder M H , Slota J E , Scarim A , Farrand S K
Published: November 2016

Mutations affecting agrocin production on the 48-kilobase (kb) plasmid, pAgK84, can be complemented in trans with cloned portions of the plasmid. Five complementation groups ranging in minimum size from 1.2 to 5.6 kb were identified within a 14-kb segment. Plasmid pAgK84-encoded immunity to agrocin 84 was located to two separate regions of the plasmid. Either region alone was sufficient to protect sensitive strains, and both loci mapped to the agrocin 84 biosynthesis region. One region is located within complementation group I, while the other forms a part of complementation group IV. Production of agrocin 84 was unaffected by nopaline, agrocinopine A, acetosyringone, or low or high levels of ferric iron. Agrocin 84 production was greatly suppressed when the strain also contained a Ti plasmid nutritionally or mutationally derepressed for agrocinopine A catabolism. RNA dot-blot analysis indicated that decreased agrocin 84 production by such strains was not due to transcriptional repression of agrocin 84 biosynthetic loci. In strains also harboring pAtK84b, the opine catabolic plasmid of Agrobacterium radiobacter K84, induction of the agrocinopine A catabolic locus of this plasmid had no such effect on agrocin 84 production.
Mutations that create new promoters suppress the sigma 54 dependence of glnA transcription in Escherichia coli
Authors: Reitzer L J , Bueno R , Cheng W D , Abrams S A , Rothstein D M , Hunt T P , Tyler B , Magasanik B
Published: November 2016

Escherichia coli rpoN mutants lack sigma 54 and are therefore unable to initiate the transcription of glnA at glnAp2, which is required for the production of a high intracellular concentration of glutamine synthetase. We have found that the dependence on sigma 54 can be overcome by mutations that have apparently created a new sigma 70-dependent promoter. The position -35 RNA polymerase contact site of this new promoter overlaps glnAp2. The initiation of transcription at the new promoter is inhibited by sigma 54-RNA polymerase even in the absence of nitrogen regulator I-phosphate, the activator required for the initiation of transcription at glnAp2. The results suggest that in cells growing with an excess of nitrogen and therefore lacking nitrogen regulator I-phosphate, sigma 54-RNA polymerase is bound at glnAp2.
Involvement of both cellulose fibrils and a Ca2+-dependent adhesin in the attachment of Rhizobium leguminosarum to pea root hair tips
Authors: Smit G , Kijne J W , Lugtenberg B J
Published: November 2016

We have previously described an assay for the attachment of Rhizobium bacteria to pea root hair tips (cap formation) which was used as a model to study the attachment step in the nodulation process. Under all conditions tested, a positive correlation was observed between the percentage of fibrillated cells and the ability of these bacteria to form caps and to adhere to glass, suggesting that fibrils play a role in the attachment of Rhizobium leguminosarum to pea root hair tips and to glass (G. Smit, J. W. Kijne, and B. J. J. Lugtenberg, J. Bacteriol. 168:821-827, 1986). In the present paper the chemical and functional characterization of the fibrils of R. leguminosarum is described. Characterization of purified fibrils by infrared spectroscopy and cellulase treatment followed by thin-layer chromatography showed that the fibrils are composed of cellulose. Purified cellulose fibrils, as well as commercial cellulose, inhibited cap formation when present during the attachment assay. Incubation of the bacteria with purified cellulase just before the attachment assay strongly inhibited cap formation, indicating that the fibrils are directly involved in the attachment process. Tn5-induced fibril-overproducing mutants showed a greatly increased ability to form caps, whereas Tn5-induced fibril-negative mutants lost this ability. None of these Tn5 insertions appeared to be located on the Sym plasmid. Both types of mutants showed normal nodulation properties, indicating that cellulose fibrils are not a prerequisite for successful nodulation under the conditions used. The ability of the fibril-negative mutants to attach to glass was not affected by the mutations, indicating that attachment to pea root hair tips and attachment to glass are (partly) based on different mechanisms. However, growth of the rhizobia under low Ca2+ conditions strongly reduced attachment to glass and also prevented cap formation, although it had no negative effect on fibril synthesis. This phenomenon was found for several Rhizobium spp. It was concluded that both cellulose fibrils and a Ca2+ -dependent adhesin(s) are involved in the attachment of R. leguminosarum to pea root hair tips. A model cap formation as a two-step process is discussed.
Sulfonamide resistance in Streptococcus pneumoniae: DNA sequence of the gene encoding dihydropteroate synthase and characterization of the enzyme
Authors: Lopez P , Espinosa M , Greenberg B , Lacks S A
Published: November 2016

A chromosomal gene of Streptococcus pneumoniae carrying a spontaneous mutation to sulfonamide resistance was identified. Comparison of its DNA sequence with the wild-type sequence showed that the mutation, sul-d, consisted of an insert of 6 base pairs, a repeat of an adjacent 6-base-pair segment. The gene encoded a 34-kilodalton polypeptide, SulA, which as a dimer or trimer constituted the enzyme dihydropteroate synthase. This was shown by enzyme activity measurements, expression in minicells of Bacillus subtilis, and the amino-terminal sequence of the polypeptide product. Subcloning of the gene in an Escherichia coli expression vector allowed purification of the enzyme to 80% homogeneity in a single step and at high yield. Although a deleted plasmid, pLS83, produced the mutant dihydropteroate synthase, it did not confer sulfonamide resistance in vivo. It is suggested that the SulA polypeptide is also a component of an enzyme that acts in another step of folate biosynthesis and that this step is inhibited in vivo by either free or conjugated sulfonamides.
Export of protein in Escherichia coli: a novel mutation in ompC affects expression of other major outer membrane proteins
Authors: Catron K M , Schnaitman C A
Published: November 2016

A mutation within the ompC structural gene of Escherichia coli K-12 which affects expression of outer membrane proteins was characterized. The mutation consisted of a 6-base-pair deletion near the 3' end of the gene which removed the amino acids Val-300 and Gly-301 of the mature coding sequence but otherwise left the reading frame intact. The deletion occurred within a region highly conserved among the porins. No protein product was detected from a single copy of the mutant gene. The mutation caused a trans-dominant decrease in the expression of a wild-type ompC allele. The mutation caused a similar decrease in the amounts of OmpA, OmpF, LamB, and Lc proteins, yet it did not appear to affect the minor outer membrane proteins. It had no significant effect on transcription from either ompF or ompC promoters as measured with lacZ operon fusions. The effects of the mutation on other proteins were completely eliminated when the signal sequence was disrupted so that the mutant protein no longer interacted with the secretion machinery of the cell but instead accumulated as precursor in the cytoplasm. A model is proposed involving the translocation of proteins to the outer membrane and the importance of protein conformation in this process.
Cloning of the ADPglucose pyrophosphorylase (glgC) and glycogen synthase (glgA) structural genes from Salmonella typhimurium LT2
Authors: Leung P S , Preiss J
Published: November 2016

The structural genes of ADPglucose pyrophosphorylase (glgC) and glycogen synthase (glgA) from Salmonella typhimurium LT2 were cloned on a 5.8-kilobase-pair insert in the SalI site of pBR322. A single strand specific radioactive probe containing the N terminus of the Escherichia coli K-12 glgC gene in M13mp8 was used to hybridize against a S. typhimurium genomic library in lambda 1059. DNA from a plaque showing a positive hybridization signal was isolated, subcloned into pBR322, and transformed into E. coli K-12 RR1 and E. coli G6MD3 (a mutant with a deletion of the glg genes). Transformants were stained with iodine for the presence of glycogen. E. coli K-12 RR1 transformants stained dark brown, whereas G6MD3 transformants stained greenish yellow, and they both were shown to contain a 5.8-kilobase-pair insert in the SalI site of pBR322, designated pPL301. Enzyme assays of E. coli K-12 G6MD3 harboring pPL301 restored ADPglucose pyrophosphorylase and glycogen synthase activities. The specific activities of ADPglucose pyrophosphorylase and glycogen synthase in E. coli K-12 RR1(pPL301) were increased 6- to 7-fold and 13- to 15-fold, respectively. Immunological and kinetic studies showed that the expressed ADPglucose pyrophosphorylase activity in transformed E. coli K-12 G6MD3 cells was very similar to that of the wild-type enzyme.
Regulation of fructose uptake and catabolism by succinate in Azospirillum brasilense
Authors: Mukherjee A , Ghosh S
Published: November 2016

Fructose uptake and catabolism in Azospirillum brasilense is dependent on three fructose-inducible enzymes (fru-enzymes): (i) enzyme I and (ii) enzyme II of the phosphoenolpyruvate:fructose phosphotransferase system and (iii) 1-phosphofructokinase. In minimal medium containing 3.7 mM succinate and 22 mM fructose as sources of carbon, growth of A. brasilense was diauxic, succinate being utilized in the first phase of growth and fructose in the second phase with a lag period between the two growth phases. None of the fru-enzymes could be detected in cells grown with succinate as the sole source of carbon, but they were detectable toward the end of the first phase of diauxie. All the fru-enzymes were coinduced by fructose and coordinately repressed by succinate. Studies on the effect of succinate on differential rates of syntheses of the fru-enzymes revealed that their induced syntheses in fructose minimal medium were subject to transient as well as permanent (catabolite) repression by succinate. Succinate also caused a similar pattern of transient and permanent repression of the fructose transport system in A. brasilense. However, no inducer (fructose) exclusionlike effect was observed as there was no inhibition of fructose uptake in the presence of succinate with fructose-grown cells even when they were fully induced for succinate uptake activity.
Identification of the DNA sequence required for transposition immunity of the gamma delta sequence
Authors: Goto N , Mochizuki A , Inagaki Y , Horiuchi S , Tanaka T , Nakaya R
Published: November 2016

A plasmid containing the transposon gamma delta sequence was immune to further insertion of gamma delta (transposition immunity). Plasmids carrying a fragment containing either 0.2 kilobase pairs of the gamma end or 0.4 kilobase pairs of the delta end of the gamma delta sequence were immune, and other parts of the gamma delta sequence did not confer immunity. The terminal 38-base-pair (bp) sequence of the delta end of the gamma delta was sufficient to confer immunity, the 38-bp sequence of the gamma end conferred only moderate immunity, and the terminal 35-bp sequence, which was completely identical at both the gamma and delta ends, was insufficient to confer immunity.
Lowering of cytoplasmic pH is essential for growth of Streptococcus faecalis at high pH
Authors: Kakinuma Y
Published: November 2016

The growth of Streptococcus faecalis at high pH was significantly stimulated by carbonate. In the absence of added carbonate the cells were unable to grow at a pH above 9.5, but in media containing 50 mM HCO3- they grew even at pH 10.5. Both rate and yield of growth at pH 9.5 were significantly stimulated by as little as 5 mM carbonate. The cytoplasmic pH in growing cells was maintained at about 7.8 to 8.2, whereas the medium pH ranged from 8.4 to 9.5. Nigericin and gramicidin D, ionophores which conduct protons, blocked growth at pH 9.5 but not at pH 7.5. These results indicate that lowering of the cytoplasmic pH is essential for the growth of this organism at high pH.
Annotating Protein Functional Residues by Coupling High-Throughput Fitness Profile and Homologous-Structure Analysis
Authors: Du Yushen , Wu Nicholas C. , Jiang Lin , Zhang Tianhao , Gong Danyang , Shu Sara , Wu Ting-Ting , Sun Ren
Published: November 2016

Identification and annotation of functional residues are fundamental questions in protein sequence analysis. Sequence and structure conservation provides valuable information to tackle these questions. It is, however, limited by the incomplete sampling of sequence space in natural evolution. Moreover, proteins often have multiple functions, with overlapping sequences that present challenges to accurate annotation of the exact functions of individual residues by conservation-based methods. Using the influenza A virus PB1 protein as an example, we developed a method to systematically identify and annotate functional residues. We used saturation mutagenesis and high-throughput sequencing to measure the replication capacity of single nucleotide mutations across the entire PB1 protein. After predicting protein stability upon mutations, we identified functional PB1 residues that are essential for viral replication. To further annotate the functional residues important to the canonical or noncanonical functions of viral RNA-dependent RNA polymerase (vRdRp), we performed a homologous-structure analysis with 16 different vRdRp structures. We achieved high sensitivity in annotating the known canonical polymerase functional residues. Moreover, we identified a cluster of noncanonical functional residues located in the loop region of the PB1 β-ribbon. We further demonstrated that these residues were important for PB1 protein nuclear import through the interaction with Ran-binding protein 5. In summary, we developed a systematic and sensitive method to identify and annotate functional residues that are not restrained by sequence conservation. Importantly, this method is generally applicable to other proteins about which homologous-structure information is available.

IMPORTANCE
To fully comprehend the diverse functions of a protein, it is essential to understand the functionality of individual residues. Current methods are highly dependent on evolutionary sequence conservation, which is usually limited by sampling size. Sequence conservation-based methods are further confounded by structural constraints and multifunctionality of proteins. Here we present a method that can systematically identify and annotate functional residues of a given protein. We used a high-throughput functional profiling platform to identify essential residues. Coupling it with homologous-structure comparison, we were able to annotate multiple functions of proteins. We demonstrated the method with the PB1 protein of influenza A virus and identified novel functional residues in addition to its canonical function as an RNA-dependent RNA polymerase. Not limited to virology, this method is generally applicable to other proteins that can be functionally selected and about which homologous-structure information is available.
Central odontogenic fibromyxoma of mandible: an aggressive odontogenic pathology
Authors: Bahl Sumit , Raju Godishala Swamy Sugunakar , Shah Gunjan , Chandarana Parvin
Published: November 2016

Myxoma of the jaws which was first described by Thoma and Goldman in 1947 is a rare neoplasm and its rate of prevalence and incidence is not available. Myxoma term, according to 1992 WHO classification, is used along with odontogenic myxoma (OM) and myxofibroma. There are two forms of myxomas or fibromyxomas that are recognised in head and neck region: one is derived from the facial skeleton and the other is derived from the soft tissue. Most of the OM are located intraosseously, but peripheral ones are also recognised. OM behaves differently from myxomatous tumours of long bones, which recur more often and may transform into malignancy. A majority of these lesions occur between 2nd and 4th decade. In the pathogenesis of OM, dental papilla, dental follicle and periodontal ligament tissues have been implicated as possible ‘germ centres’. This case describes an uncommon finding of central odontogenic fibromyxoma, throwing light on its epidemiology, clinical, histopathology, molecular and treatment aspects.
Association between maternal education and malocclusion in Mongolian adolescents: a cross-sectional study
Authors: Tumurkhuu Tsasan , Fujiwara Takeo , Komazaki Yuko , Kawaguchi Yoko , Tanaka Toshihiro , Inazawa Johji , Ganburged Ganjargal , Bazar Amarsaikhan , Ogawa Takuya , Moriyama Keiji
Published: November 2016

Objective

Malocclusion is a highly prevalent condition, affecting 20–60% of adolescents worldwide. Although its treatment is often expensive and unaffordable for disadvantaged individuals, few studies have examined the relationship between malocclusion and socioeconomic status. We investigated the prevalence of malocclusion among Mongolian adolescents and its association with maternal education in a community-based sample in Mongolia.

Design

Cross-sectional study.

Settings

2 large secondary schools with different backgrounds in Ulaanbaatar, Mongolia.

Participants

Complete dental casts of 557 randomly recruited Mongolian schoolchildren aged 11–16 years were evaluated using the Dental Health Component of the Index of Orthodontic Treatment Need to dichotomise orthodontic treatment requirements. Exclusion criteria were the presence of orthodontic treatment history and absence of maternal educational status. Questionnaires were administered to caregivers to assess socioeconomic status. Poisson regression analysis was performed to examine the association between malocclusion and maternal educational status.

Results

The prevalence of malocclusion requiring orthodontic treatment among all adolescents was 35.2% (95% CI 31.2 to 39.2). In the unadjusted analysis, the prevalence ratio (PR) for malocclusion was higher (PR=1.46; 95% CI 0.96 to 2.20) among adolescents of mothers with a high educational background than among those of mothers with a low educational background. After adjusting for covariates, the PR remained significantly higher (PR=1.72; 95% CI 1.06 to 2.82) among adolescents of mothers with a high educational background. Other socioeconomic status variables, including family income and the educational level of the father, showed no association with malocclusion.

Conclusions

These findings suggest that malocclusion requiring orthodontic treatment in adolescents is more prevalent among children of mothers with high levels of education. Further studies are needed to clarify the behavioural factors and environmental circumstance that contribute to this.
Histopathological Evaluation and Expression of the Pluripotent Mesenchymal Stem Cell-Like Markers Cd105 and Cd44 in the Synovial Membrane of Patients with Primary versus Secondary Hip Osteoarthritis
Authors: Turdean Sabin Gligore , Jung Ioan , Gurzu Simona , Zazgyva Ancuta , Fetyko Annamaria , Roman Ciprian Oliviu , Turcu Mihai , Pop Tudor Sorin
Published: November 2016

To present the morphological changes of classic primary versus rapidly progressive and secondary hip osteoarthritis (HO) and to examine the expression of two pluripotent mesenchymal stem cell-like markers in the synovial membrane. A prospective observational study was conducted in 57 consecutive cases of radiologically confirmed HO in which total hip arthroplasty was performed. Based on the radiological and clinicopathological features, the cases were divided into three categories: classic primary HO (group A; n=16), rapidly destructive HO (group B; n=24), and HO secondary to avascular osteonecrosis of the femoral head (group C; n=17). Immunostains were performed using the markers CD44 and CD105. The cases from group A were mainly characterized by a marked perivascular inflammatory infiltrate and simple synovial hyperplasia. In group B, the papillary type of synovial hyperplasia was found and presence of chondromatosis, ossification, and ectopic follicles with germinal centers in the subsynovial layer was characteristic, whereas marked calcification and/or ossification were seen in group C. Focal expression of the CD105 and CD44 was noted in the hyperplastic synovial cells and subsynovial layer in cases from group A, whereas synovial cells from group B were diffusely positive for both CD44 and CD105. In secondary HO, CD44 marked the inflammatory cells. Mobilization of the CD44/CD105 positive synovial cells seems to play a role in the genesis of HO. The number of the pluripotent mesenchymal stem cell-like cells derived from the hyperplastic synovial cells might be related to the severity of possible immune-mediated rapidly destructive HO.
Molecular factors involved in the hypolipidemic- and insulin-sensitizing effects of a ginger (Zingiber officinale Roscoe) extract in rats fed a high-fat diet
Authors: de las Heras Natalia , Valero-Muñoz María , Martín-Fernández Beatriz , Ballesteros Sandra , López-Farré Antonio , Ruiz-Roso Baltasar , Lahera Vicente
Published: November 2016

Hypolipidemic and hypoglycemic properties of ginger in animal models have been reported. However, information related to the mechanisms and factors involved in the metabolic effects of ginger at a hepatic level are limited. The aim of the present study was to investigate molecular factors involved in the hypoglycemic and hypolipidemic effects of a hydroethanolic ginger extract (GE) in the liver of rats fed a high-fat diet (HFD). The study was conducted in male Wistar rats divided into the following 3 groups: (i) Rats fed a standard diet (3.5% fat), the control group; (ii) rats fed an HFD (33.5% fat); and (iii) rats fed an HFD treated with GE (250 mg·kg−1·day−1) for 5 weeks (HFD+GE). Plasma levels of glucose, insulin, lipid profile, leptin, and adiponectin were measured. Liver expression of glycerol phosphate acyltransferase (GPAT), cholesterol 7 alpha-hydroxylase, peroxisome proliferator-activated receptors (PPAR), PPARα and PPARγ, glucose transporter 2 (GLUT-2), liver X receptor, sterol regulatory element-binding protein (SREBP1c), connective tissue growth factor (CTGF), and collagen I was measured. Data were analyzed using a 1-way ANOVA, followed by a Newman−Keuls test if differences were noted. The study showed that GE improved lipid profile and attenuated the increase of plasma levels of glucose, insulin, and leptin in HFD rats. This effect was associated with a higher liver expression of PPARα, PPARγ, and GLUT-2 and an enhancement of plasma adiponectin levels. Furthermore, GE reduced liver expression of GPAT, SREBP1c, CTGF, and collagen I. The results suggest that GE might be considered as an alternative therapeutic strategy in the management of overweight and hepatic and metabolic−related alterations.
Ethanol-dependent expression of the NKG2D ligands MICA/B in human cell lines and leukocytes
Authors: Streltsova Maria A. , Klinkova Anna V. , Kuchukova Anastasia A. , Kadin Andrey Y. , Kanevskiy Leonid M. , Kovalenko Elena I.
Published: November 2016

Alcohol consumption affects the human immune system, causing a variety of disorders. However, the mechanisms of development of these changes are not fully understood. We hypothesized that ethanol may influence the expression of MICA and MICB, stress-induced molecules capable of regulating the activity of cytotoxic lymphocytes through the interaction with receptor NKG2D, which substantially affects the functionality of cellular immunity. We analyzed the effects of ethanol on MICA/B expression in tumor cell lines and human leukocytes. In the cell line models, ethanol caused different changes in the surface expression of MICA/B; in particular, it induced the translocation of intracellular proteins MICA/B to the cell surface and shedding of MICA (in soluble and microparticle-associated forms) from the plasma membrane. The observed results are not linked with cell death in cultures, taking place only under higher doses of ethanol. Ethanol at physiologically relevant concentrations (and higher) stimulated expression of MICA/B genes in different cell types. The effect of ethanol was more pronounced in hepatocyte line HepG2 compared with hematopoietic cell lines K562, Jurkat, and THP-1. Among the tested leukocytes, the most sensitive to ethanol action were T cells activated ex vivo with IL-2, in which the increase of MICA/B mRNA expression was registered with the smallest dose of ethanol (0.125%). In human monocytes, ethanol may lead to elevations in surface MICA/B levels. Presumably, changes in MICA/B expression caused by ethanol can affect the functions of NKG2D-positive cytotoxic lymphocytes, modulating immune reactions at excessive alcohol consumption.
A deletion variant partially complements a porin-less strain ofNeurospora crassa
Authors: Ferens Fraser G. , Spicer Victor , Krokhin Oleg V. , Motnenko Anna , Summers William A.T. , Court Deborah A.
Published: November 2016

Mitochondrial porin, the voltage-dependent anion channel, plays an important role in metabolism and other cellular functions within eukaryotic cells. To further the understanding of porin structure and function, Neurospora crassa wild-type porin was replaced with a deletion variant lacking residues 238–242 (238porin). 238porin was assembled in the mitochondrial outer membrane, but the steady state levels were only about 3% of those of the wild-type protein. The strain harbouring 238porin displayed cytochrome deficiencies and expressed alternative oxidase. Nonetheless, it exhibited an almost normal linear growth rate. Analysis of mitochondrial proteomes from a wild-type strain FGSC9718, a strain lacking porin (ΔPor-1), and one expressing only 238porin, revealed that the major differences between the variant strains were in the levels of subunits of the NADH:ubiquinone oxidoreductase (complex I) of the electron transport chain, which were reduced only in the ΔPor-1 strain. These, and other proteins related to electron flow and mitochondrial biogenesis, are differentially affected by relative porin levels.
A hierarchical planning system to assess the impact of operational-level flexibility on long-term wood supply
Authors: Gautam Shuva , LeBel Luc , Beaudoin Daniel
Published: November 2016

Operational-level flexibility in the choice of silvicultural treatments allows mitigatation of the impact of uncertain demand on supply chain performance. Silvicultural treatments dictate the species and quantity harvested from forest stands. However, their impact on wood supply sustainability is not clearly understood. This study proposes a simulation–optimization system to model hierarchical forest management planning with an objective to examine the impact. The system consists of mathematical models to develop hierarchical plans, i.e., strategic, tactical, and operational. In the system, the strategic model is first solved to determine the annual allowable cut. Next, the tactical model allocates cutblocks to annual plans, also prescribing silvicultural treatments. The subsequent operational-level model generates monthly plans in a rolling planning basis to satisfy prevailing demand. Upon execution of all operational-level plans, the forest inventory is updated and the change in annual allowable cut is evaluated. The system was implemented in a case study in Quebec, Canada. Permitting silvicultural flexibility at the operational level led to profit improvements between 2% and 3.7% over a 100 year horizon. Significant impact on long-term wood supply was not observed in this case. The proposed system can help forest planners and supply chain managers better integrate their respective needs.
On corollary model-dependent analyses and comparisons
Authors: Bernabei R. , Belli P. , Incicchitti A. , Cerulli R. , Dai C. J. , Ma X. H. , Ye Z. P.
Published: November 2016

Some theoretical and experimental aspects regarding the direct dark matter field are mentioned. In particular some arguments, which play a relevant role in the evaluation of model-dependent interpretations of experimental results and in comparisons, are shortly addressed.
When do links admit homeomorphic C-complexes?
Authors: Davis Christopher W. , Roth Grant
Published: November 2016

Any two knots admit orientation preserving homeomorphic Seifert surfaces, as can be seen by stabilizing. There is a generalization of a Seifert surface to the setting of links called a [Formula: see text]-complex. In this paper, we ask when two links will admit orientation preserving homeomorphic [Formula: see text]-complexes. In the case of 2-component links, we find that the pairwise linking number provides a complete obstruction. In the case of links with 3 or more components and zero pairwise linking number, Milnor’s triple linking number provides a complete obstruction.
Improved Integral Formulation for Acoustic Radiation Using Integral Equation of Frequency Averaged Quadratic Pressure
Authors: Gao Honglin , Li Sheng
Published: November 2016

This paper is concerned with the problem of obtaining a unique solution for radiation at irregular frequencies when an integral equation of frequency averaged quadratic pressure (FAQP) is used to get robust predictions at medium and high frequencies. It is proved that there is no unique solution of the integral equation of FAQP at irregular frequencies, and existence and uniqueness of solutions under four types of boundary conditions are discussed. A combined energy boundary integral equation formulation (CEBIEF) is presented and proves to be efficient to overcome the nonuniqueness of the integral equation of FAQP. The numerical examples are given to demonstrate the versatility of the CEBIEF method with a proposed function correctly indicating a solution.
EFFECTS OF TiO2 FILM THICKNESS AND ELECTROLYTE CONCENTRATION ON PHOTOVOLTAIC PERFORMANCE OF DYE-SENSITIZED SOLAR CELL
Authors: DOMTAU D. L. , SIMIYU J. , AYIETA E. O. , NYAKITI L. O. , MUTHOKA B. , MWABORA J. M.
Published: November 2016

Effects of film thickness and electrolyte concentration on the photovoltaic performance of TiO2-based dye-sensitized solar cell (DSSC) were studied. Nanocrystalline anatase TiO2 thin films with varying thicknesses (3.2–18.9[Formula: see text][Formula: see text]m) have been deposited on FTO/glass substrates by screen printing method as work electrodes for DSSC. The prepared samples were characterized by UV-Vis spectroscopy, Atomic Force Microscopy/Scanning Tunneling Microscopy (AFM/STM) and X-ray diffraction (XRD). The optimal thickness of the TiO2 photoanode is 13.5[Formula: see text][Formula: see text]m. Short-circuit photocurrent density ([Formula: see text]) increases with film thickness due to enlargement of surface area whereas open-circuit voltage decreases with increase in thickness due to increase in electron diffusion length to the electrode. However, the [Formula: see text] and [Formula: see text] of DSSC with a film thickness of 18.9[Formula: see text][Formula: see text]m (7.5[Formula: see text]mA/cm2 and 0.687[Formula: see text]V) are smaller than those of DSSC with a TiO2 film thickness of 13.5[Formula: see text][Formula: see text]m (9.9[Formula: see text]mA/cm2 and 0.734[Formula: see text]V). This is because the increased thickness of TiO2 thin film resulted in the decrease in the transmittance of TiO2 thin films hence reducing the incident light intensity on the N719 dye. Photovoltaic performance also depends greatly on the redox couple concentration in iodide[Formula: see text]triiodide. [Formula: see text] decreases as the redox concentration increases as a result of increased viscosity of the solution which lowers ion mobility. Similarly, [Formula: see text] decreases as the electrolyte concentration increases due to enhanced back electron transfer reaction. An optimum power conversion efficiency of 4.3% was obtained in a DSSC with the TiO2 film thickness of 13.5[Formula: see text][Formula: see text]m and redox concentration of 0.03[Formula: see text]mol dm[Formula: see text] under AM 1.5G illumination at 100[Formula: see text]mW/cm2.
CORROSION AND WEAR PROPERTIES OF ELECTRODEPOSITED TERTIARY NANOCOMPOSITE Zn–Ni (ALUMINA–YITTRIA–GERAPHENE) COATING
Authors: RAHMANI HAMED , ALIOFKHAZRAEI MAHMOOD , KARIMZADEH ABDOSSALAM
Published: November 2016

Nanocomposite Ni–Zn coatings containing 80 wt.% Al2O3, 5 wt.% Y2O3 and 15 wt.% graphene were fabricated by pulsed electrodeposition method in nickel–zinc sulphate-based electrolyte and effects of pulse current parameters on nickel and other element contents, microstructure, resistance to corrosion and tribological properties of the coatings were investigated. The pulsed current with duty cycle from 10% to 50% was applied to different samples and frequency changed gradually from 500 to 4000[Formula: see text]Hz in five steps during coating process. Increasing the duty cycle led to decrease of absorbed nanoparticles in the surface of the coatings from 4.4 vol% to 3.58 vol% The sample coated with 10% duty cycle had utmost alumina content in the coating surface, 3.5 vol% in first layer up to 4.4 vol% in fifth layer. The sample coated with 30% duty cycle had higher corrosion resistance with passive current density of 2.5[Formula: see text]mA/cm2. Furthermore, the results showed that by increasing the duty cycle, wear rate had been increased up to 1.3[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text][Formula: see text]mm2/N[Formula: see text]m.
THE EFFECT OF CARBURIZATION OF ASTM A36 STEEL SUBSTRATE IN IMPROVING WEAR PROPERTIES OF PLASMA SPRAYED WC–12%Co COATING
Authors: KARUPPUSWAMY P. , BHAGYANATHAN C. , NARENDHAR C. , KIRUPAKARAN R. N. , ARUN KUMAR S. D.
Published: November 2016

Thermally sprayed coating is commonly used to modify the surface to improve the mechanical properties of the substrates to meet their functional requirements. Numerous research works were carried out to assess the suitability of the WC–Co coating for industrial applications using thermal spray process. Meanwhile, few researchers expressed about the deterrent effect of the decarburization on mechanical properties of the coating due to processing at high temperature in thermal spray process which reduces the efficiency of the coating process. In this research work, coating of WC–12%Co powder over ASTM A36 steel substrate through plasma spray process was considered to investigate the effect of introducing the carburization process on wear properties of the resultant coating. Carburization process was introduced on the ASTM A36 steel substrate before the application of the plasma spray coating to compensate the loss of carbon during the process. Characterization of the deposited coating was done by scanning electron microscope, X-ray diffraction, hardness, corrosive resistivity test and wear tests. The results of the tests indicated that introduction of the carburization process remarkably increased the hardness of the coating and corrosive resistivity besides improving the wear resistance.
On tetravalent s-regular Cayley graphs
Authors: Li Jing Jian , Ling Bo , Ma Jicheng
Published: November 2016

A Cayley graph [Formula: see text] is said to be core-free if [Formula: see text] is core-free in some [Formula: see text] for [Formula: see text]. A graph [Formula: see text] is called [Formula: see text]-regular if [Formula: see text] acts regularly on its [Formula: see text]-arcs. It is shown in this paper that if [Formula: see text], then there exist no core-free tetravalent [Formula: see text]-regular Cayley graphs; and for [Formula: see text], every tetravalent [Formula: see text]-regular Cayley graph is a normal cover of one of the three known core-free graphs. In particular, a characterization of tetravalent [Formula: see text]-regular Cayley graphs is given.