bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic evidence that the XylS regulator of the Pseudomonas TOL meta operon controls the Pm promoter through weak DNA-protein interactions
Authors: Kessler B , Herrero M , Timmis K N , de Lorenzo V
Published: November 2016

The activation of the Pm promoter of the meta operon of the TOL plasmid of Pseudomonas putida by its cognate XylS activator protein in the presence and absence of benzoate inducers has been examined in specialized Escherichia coli strains carrying Pm-lacZ fusions and the xylS gene in different configurations in which all controlling elements are present in near native conditions and stoichometry. Expression of a chromosomal Pm-xylX::lacZ fusion was primarily dependent on the addition of an effector at a low xylS gene dosage, but such dependency decreased with increasing levels of the regulator, to the point that hyperproduced XylS could, in the absence of any aromatic effector, raise expression to a level 10(4)-fold higher than normal basal levels. Pm activity never reached a defined saturation level within the range of intracellular concentrations permitted by the intrinsic solubility of the protein, thus suggesting a low degree of occupancy of the OmR and OmL (Om right and left half-sites, respectively) operator sequences by XylS. This was confirmed by transcription interference experiments, which indicated that the frequency of occupation of Pm by active XylS is low. This property permits a fine tuning of Pm activity in vivo through changes in intracellular XylS concentrations, as is predicted in current models to account for the coordinated regulation of TOL operons.
A role for residue 151 of LamB in bacteriophage lambda adsorption: possible steric effect of amino acid substitutions
Authors: Charbit A , Werts C , Michel V , Klebba P E , Quillardet P , Hofnung M
Published: November 2016

LamB is the cell surface receptor for bacteriophage lambda. LamB missense mutations yielding resistance to lambda have been previously grouped in two classes. Class I mutants block growth of lambda with wild-type host range (lambda h+) but support growth of one-step extended-host-range mutants (lambda h). Class II mutants block lambda h but support growth of two-step extended host range mutants (lambda hh*). While Class I mutations occur at 11 different amino acid sites, in five distinct portions of LamB, all the Class II mutations analyzed previously correspond to the same G-to-D change at amino acid 151. We generated by in vitro mutagenesis four different new substitutions at site 151 (to S, V, R, and C). Two of the mutants (G-151-->V [G151V] and G151R) were of Class II, while the two others (G151S and G151C) were of Class I, demonstrating that not only the site but also the nature of the substitutions at residue 151 was critical for the phage sensitivity phenotypes. The introduction of a negatively charged, a positively charged, or an aliphatic nonpolar residue at site 151 of LamB prevented both lambda h+ and lambda h adsorption, indicating that the block is not due to a charge effect. In contrast to G151D, which was sensitive to all the lambda hh* phages, G151V and G151R conferred sensitivity to only four of the five lambda hh* phages. Thus, G151V and G151R represent a new subclass of Class II LamB mutations that is more restrictive with respect to the growth of lambda hh*. Our results agree with the hypothesis that residue 151 belongs to an accessibility gate controlling the access to the phage tight-binding site and that substitutions at this residue affect the access of the phage to the binding site in relation to the size of the substitute side chain (surface area): the most restrictive changes are G151V and G151R, followed to a lesser extent by G151D and they by G151S and G151C.
Biochemical properties of a novel metalloprotease from Staphylococcus hyicus subsp. hyicus involved in extracellular lipase processing
Authors: Ayora S , Lindgren P E , Götz F
Published: November 2016

Two extracellular proteases from Staphylococcus hyicus subsp. hyicus, ShpI and ShpII, have been characterized. ShpI is a neutral metalloprotease with broad substrate specificity; the gene has been cloned and sequenced. ShpII, characterized here, is mainly produced in the late logarithmic growth phase in contrast to ShpI, which is mainly produced in the late stationary growth phase. ShpII was purified from culture medium of S. hyicus by ammonium sulfate precipitation and DEAE-Sepharose chromatography. The molecular mass, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was 34 kDa. The temperature optimum of ShpII was 55 degrees C, and the pH optimum was 7.4. ShpII, a neutral metalloprotease, was strongly inhibited by zinc and calcium chelators. The amino-terminal sequence of the active enzyme was similar to the corresponding region of a Staphylococcus epidermidis metalloprotease. The substrate specificity of ShpII was similar to that of thermolysin-like proteases, with the exception that ShpII also recognized aromatic amino acids. We demonstrated in vitro that ShpII, but not ShpI, cleaved the 86-kDa S. hyicus subsp. hyicus prolipase between Thr-245 and Val-246 to generate the mature 46-kDa lipase. Results of additional in vivo experiments supported the model that ShpII is necessary for the extracellular processing and maturation of S. hyicus subsp. hyicus lipase.
Phosphoenolpyruvate-dependent maltose:phosphotransferase activity in Fusobacterium mortiferum ATCC 25557: specificity, inducibility, and product analysis
Authors: Robrish S A , Fales H M , Gentry-Weeks C , Thompson J
Published: November 2016

Phosphoenolypyruvate-dependent maltose:phosphotransferase activity was induced in cells of Fusobacterium mortiferum ATCC 25557 during growth on maltose. The disaccharide was rapidly metabolized by washed cells maintained under anaerobic conditions, but fermentation ceased immediately upon exposure of the cell suspension to air. Coincidentally, high levels of a phosphorylated derivative accumulated within the cells. Chemical and enzymatic analyses, in conjunction with data from 1H, 13C, and 31P nuclear magnetic resonance spectroscopy, established the structure of the purified compound as 6-O-phosphoryl-alpha-D-glucopyranosyl-(1-4)-D-glucose (maltose 6-phosphate). A method for the preparation of substrate amounts of this commercially unavailable disaccharide phosphate is described. Permeabilized cells of F. mortiferum catalyzed the phosphoenolpyruvate-dependent phosphorylation of maltose under aerobic conditions. However, the hydrolysis of maltose 6-phosphate (to glucose 6-phosphate and glucose) by permeabilized cells or cell-free preparations required either an anaerobic environment or addition of dithiothreitol to aerobic reaction mixtures. The first step in dissimilation of the phosphorylated disaccharide appears to be catalyzed by an oxygen-sensitive maltose 6-phosphate hydrolase. Cells of F. mortiferum, grown previously on maltose, fermented a variety of alpha-linked glucosides, including maltose, turanose, palatinose, maltitol, alpha-methylglucoside, trehalose, and isomaltose. Conversely, cells grown on the separate alpha-glucosides also metabolized maltose. For this anaerobic pathogen, we suggest that the maltose:phosphotransferase and maltose 6-phosphate hydrolase catalyze the phosphorylative translocation and cleavage not only of maltose but also of structurally analogous alpha-linked glucosides.
Infection of soybean and pea nodules by Rhizobium spp. purine auxotrophs in the presence of 5-aminoimidazole-4-carboxamide riboside
Authors: Newman J D , Diebold R J , Schultz B W , Noel K D
Published: November 2016

Purine auxotrophs of various Rhizobium species are symbiotically defective, usually unable to initiate or complete the infection process. Earlier studies demonstrated that, in the Rhizobium etli-bean symbiosis, infection by purine auxotrophs is partially restored by supplementation of the plant medium with 5-amino-imidazole-4-carboxamide (AICA) riboside, the unphosphorylated form of the purine biosynthetic intermediate AICAR. The addition of purine to the root environment does not have this effect. In this study, purine auxotrophs of Rhizobium fredii HH303 and Rhizobium leguminosarum 128C56 (bv. viciae) were examined. Nutritional and genetic characterization indicated that each mutant was blocked in purine biosynthesis prior to the production of AICAR. R. fredii HH303 and R. leguminosarum 128C56 appeared to be deficient in AICA riboside transport and/or conversion into AICAR, and the auxotrophs derived from them grew very poorly with AICA riboside as a purine source. All of the auxotrophs elicited poorly developed, uninfected nodules on their appropriate hosts. On peas, addition of AICA riboside or purine to the root environment led to enhanced nodulation; however, infection threads were observed only in the presence of AICA riboside. On soybeans, only AICA riboside was effective in enhancing nodulation and promoting infection. Although AICA riboside supplementation of the auxotrophs led to infection thread development on both hosts, the numbers of bacteria recovered from the nodules were still 2 or more orders of magnitude lower than in fully developed nodules populated by wild-type bacteria. The ability to AICA riboside to promote infection by purine auxotrophs, despite serving as a very poor purine source for these strains, supports the hypothesis that AICAR plays a role in infection other than merely promoting bacterial growth.
Transcriptional regulation of the Bacillus subtilis glucitol dehydrogenase gene
Authors: Ye R , Wong S L
Published: November 2016

The regulatory region of the Bacillus subtilis glucitol dehydrogenase (gutB) gene was divided into three subregions: a promoter, an upstream positive regulatory region, and a downstream negative regulatory region. Data from primer extension, deletion, and site-directed mutagenesis analyses were consistent with two possible models for the gutB promoter. It is either a sigma A-type promoter with an unusually short spacer region (15 bp) or a special sigma A promoter which requires only the hexameric -10 sequence for its function. Sequence carrying just the promoter region (from -48 to +6) failed to direct transcription in vivo. An upstream regulatory sequence was essential for glucitol induction. When this sequence was inserted in a high-copy-number plasmid, an effect characteristic of titration of a transcriptional activator was seen. Downstream from the promoter, there is an imperfect, AT-rich inverted repeat sequence. Deletion of this element did not lead to constitutive expression of gutB. However, the induced gutB expression level was enhanced three- to fourfold.
Loss of protein kinase-catalyzed phosphorylation of HPr, a phosphocarrier protein of the phosphotransferase system, by mutation of the ptsH gene confers catabolite repression resistance to several catabolic genes of Bacillus subtilis
Authors: Deutscher J , Reizer J , Fischer C , Galinier A , Saier M H , Steinmetz M
Published: November 2016

In gram-positive bacteria, HPr, a phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system (PTS), is phosphorylated by an ATP-dependent, metabolite-activated protein kinase on seryl residue 46. In a Bacillus subtilis mutant strain in which Ser-46 of HPr was replaced with a nonphosphorylatable alanyl residue (ptsH1 mutation), synthesis of gluconate kinase, glucitol dehydrogenase, mannitol-1-P dehydrogenase and the mannitol-specific PTS permease was completely relieved from repression by glucose, fructose, or mannitol, whereas synthesis of inositol dehydrogenase was partially relieved from catabolite repression and synthesis of alpha-glucosidase and glycerol kinase was still subject to catabolite repression. When the S46A mutation in HPr was reverted to give S46 wild-type HPr, expression of gluconate kinase and glucitol dehydrogenase regained full sensitivity to repression by PTS sugars. These results suggest that phosphorylation of HPr at Ser-46 is directly or indirectly involved in catabolite repression. A strain deleted for the ptsGHI genes was transformed with plasmids expressing either the wild-type ptsH gene or various S46 mutant ptsH genes (S46A or S46D). Expression of the gene encoding S46D HPr, having a structure similar to that of P-ser-HPr according to nuclear magnetic resonance data, caused significant reduction of gluconate kinase activity, whereas expression of the genes encoding wild-type or S46A HPr had no effect on this enzyme activity. When the promoterless lacZ gene was put under the control of the gnt promoter and was subsequently incorporated into the amyE gene on the B. subtilis chromosome, expression of beta-galactosidase was inducible by gluconate and repressed by glucose. However, we observed no repression of beta-galactosidase activity in a strain carrying the ptsH1 mutation. Additionally, we investigated a ccpA mutant strain and observed that all of the enzymes which we found to be relieved from carbon catabolite repression in the ptsH1 mutant strain were also insensitive to catabolite repression in the ccpA mutant. Enzymes that were repressed in the ptsH1 mutant were also repressed in the ccpA mutant.
The DNA damage-inducible dinD gene of Escherichia coli is equivalent to orfY upstream of pyrE
Authors: Lundegaard C , Jensen K F
Published: November 2016

The DNA damage-inducible gene dinD, originally identified by Kenyon and Walker (C. J. Kenyon and G. C. Walker, Proc. Natl. Acad. Sci. USA 77:2819-2823, 1980) by selection of the dinD::MudI (Ap lac) fusion, is shown here to be equivalent to the open reading frame orfY near pyrE. The evidence for identity between the two genes includes results from P1 transduction, Southern hybridization, and cloning and sequencing of the dinD fusion. No data were obtained that reveal any hints about the function of the dinD gene.
Primary structures of the wild-type and mutant alleles encoding the phosphatidylglycerophosphate synthase of Escherichia coli
Authors: Usui M , Sembongi H , Matsuzaki H , Matsumoto K , Shibuya I
Published: November 2016

The nucleotide sequence of the Escherichia coli pgsA gene, encoding phosphatidylglycerophosphate synthase, is revised to code for an enzyme of 182 amino acid residues, instead of the 216 of a previous work (A. S. Gopalakrishnan, Y.-C. Chen, M. Temkin, and W. Dowhan, J. Biol. Chem. 261:1329-1338, 1986). The revised structure now explains the properties of the enzyme. Three pgsA mutants of different phenotypes were also analyzed: pgsA3, pgsA36, and pgsA10 have single-base replacements in codons 60 (Thr-->Pro), 1 (ATG-->ATA), and 92 (Thr-->Ile), respectively.
Thirty-three amino acids of the mature moiety of an unprocessed maltose-binding protein are sufficient for export in Escherichia coli
Authors: Barkocy-Gallagher G A , Cannon J G , Bassford P J
Published: November 2016

Maltose-binding protein (MBP) is translocated across the cytoplasmic membrane of Escherichia coli; successful export depends on information in both the signal peptide and the mature moiety of the protein. To determine the shortest portion of the mature region that would maintain detectable entry of MBP into the export pathway, we took advantage of the properties of an MBP species with proline substituted in the +1 position relative to the cleavage site (MBP27-P). This protein efficiently crosses the cytoplasmic membrane but is not processed and acts as a competitive inhibitor of signal peptidase I (leader peptidase). Export of MBP27-P is measured by the inhibition of processing of other proteins, such as ribose-binding protein (RBP). A series of truncated derivatives of MBP27-P were tested for the ability to inhibit processing of RBP. An MBP27-P species with only 33 amino acids of the mature moiety inhibited processing of RBP, indicating that this truncated polypeptide was probably exported and interacted with signal peptidase I.
Cloning and sequencing of the genes from Salmonella typhimurium encoding a new bacterial ribonucleotide reductase
Authors: Jordan A , Gibert I , Barbé J
Published: November 2016

A plasmid library of Salmonella typhimurium was used to complement a temperature-sensitive nrdA mutant of Escherichia coli. Complementation was obtained with two different classes of plasmids, one carrying the E. coli nrdAB-like genes and the second containing an operon encoding a new bacterial ribonucleotide reductase. Plasmids harboring these new reductase genes also enable obligately anaerobic nrdB::Mud1 E. coli mutants to grow in the presence of oxygen. This operon consists of two open reading frames, which have been designated nrdE (2,145 bp) and nrdF (969 bp). The deduced amino acid sequences of the nrdE and nrdF products include the catalytically important residues conserved in ribonucleotide reductase enzymes of class I and show 25 and 28% overall identity with the R1 and R2 protein, respectively, of the aerobic ribonucleoside diphosphate reductase of E. coli. The 3' end of the sequenced 4.9-kb fragment corresponds to the upstream region of the previously published proU operon of both S. typhimurium and E. coli, indicating that the nrdEF genes are at 57 min on the chromosomal maps of these two bacterial species. Analysis of the nrdEF and proU sequences demonstrates that transcription of the nrdEF genes is in the clockwise direction on the S. typhimurium and E. coli maps.
Biodegradation of 4-methyl-5-nitrocatechol by Pseudomonas sp. strain DNT
Authors: Haigler B E , Nishino S F , Spain J C
Published: November 2016

Pseudomonas sp. strain DNT degrades 2,4-dinitrotoluene (DNT) by a dioxygenase attack at the 4,5 position with concomitant removal of the nitro group to yield 4-methyl-5-nitrocatechol (MNC). Here we describe the mechanism of removal of the nitro group from MNC and subsequent reactions leading to ring fission. Washed suspensions of DNT-grown cells oxidized MNC and 2,4,5-trihydroxytoluene (THT). Extracts prepared from DNT-induced cells catalyzed the disappearance of MNC in the presence of oxygen and NADPH. Partially purified MNC oxygenase oxidized MNC in a reaction requiring 1 mol of NADPH and 1 mol of oxygen per mol of substrate. The enzyme converted MNC to 2-hydroxy-5-methylquinone (HMQ), which was identified by gas chromatography-mass spectrometry. HMQ was also detected transiently in culture fluids of cells grown on DNT. A quinone reductase was partially purified and shown to convert HMQ to THT in a reaction requiring NADH. A partially purified THT oxygenase catalyzed ring fission of THT and accumulation of a compound tentatively identified as 3-hydroxy-5-(1-formylethylidene)-2-furanone. Preliminary results indicate that this compound is an artifact of the isolation procedure and suggest that 2,4-dihydroxy-5-methyl-6-oxo-2,4-hexadienoic acid is the actual ring fission product.
When Obligate Partners Melt Down
Authors: Moran Nancy A.
Published: November 2016

Insect hosts derive benefits from their obligate symbionts, including nutrient supplementation and the ability to colonize otherwise inhospitable niches. But long-term symbionts sometimes also limit the ecological range of their hosts; in particular, they are often more temperature sensitive than the hosts themselves. Even small increases in average temperature, comparable to those occurring under current conditions of climate change, can kill symbionts and, with them, their hosts. In some cases, limitations imposed by obligate symbionts may help to counter the spread of invasive pests, but they also contribute to contractions in populations and geographic ranges of invertebrate species.
Siderophores: More than Stealing Iron
Authors: Behnsen Judith , Raffatellu Manuela
Published: November 2016

Siderophores are small molecular iron chelators that are produced by microbes and whose most notable function is to sequester iron from the host and provide this essential metal nutrient to microbes. Recent studies have proposed additional, noncanonical roles for siderophores, including the acquisition of noniron metals and modulation of host functions. Recently, Holden et al. (V. I. Holden, P. Breen, S. Houle, C. M. Dozois, and M. A. Bachman, mBio 7:e01397-16, 2016,
http://dx.doi.org/10.1128/mBio.01397-16
) showed that siderophores secreted by
Klebsiella pneumoniae
during lung infection induce stabilization of the transcription factor HIF-1α, increase the expression of proinflammatory cytokines in the lung, and promote dissemination of
K. pneumoniae
to the spleen. Thus, their study demonstrated novel roles for siderophores
in vivo
, beyond iron sequestration. The interaction of siderophores with host cells further promotes the pathogenicity of
K. pneumoniae
and is likely relevant for other pathogens that also secrete siderophores in the host.
Cooperative Evolutionary Strategy between the Bacteriome and Mycobiome
Authors: Ghannoum Mahmoud
Published: November 2016

Nonhealing chronic wounds are all unique in origin and circumstance, and attempting to isolate a single etiology for the failure of a wound to heal is daunting. Wounds represent complex systems of multispecies fungal and bacterial biofilms. The survival strategies of interactive microbial communities have led to cooperative evolutionary strategies that culminate in biofilm formation. In microbial dysbiosis, biofilms are beneficial to both bacterial and fungal communities but detrimental to the host. Fungi benefit by a surge in their virulence factors, while bacteria become tolerant to antibacterials as a consequence of living under the protective umbrella of the biofilm matrix. This interkingdom cooperation negatively impacts the host, as the fungi and bacteria produce extracellular enzymes that inflict tissue damage, leading to an increase in proinflammatory cytokines, which results in oxidative damage and apoptotic cell death.
Contained rupture of a mycotic infrarenal aortic aneurysm infected withCampylobacter fetus
Authors: Dimitrief Maria , Cherbanyk Floryn , Déglise Sébastien , Pezzetta Edgardo
Published: November 2016

Mycotic abdominal aortic aneurysms (MAAAs) are rare entities accounting for 0.65–2% of aortic aneurysms.Campylobacter fetushas a tropism for vascular tissue and is a rare cause of mycotic aneurysm. We present a 73-year-old male patient with contained rupture of a MAAA caused byC. fetus, successfully treated with endovascular aortic repair (EVAR) and antibiotics, which is not previously described for this aetiology. Although open surgery is the gold standard, EVAR is nowadays feasible and potentially represents a durable option, especially in frail patients.
Cross-sectional survey of the amount of free sugars and calories in carbonated sugar-sweetened beverages on sale in the UK
Authors: Hashem Kawther M , He Feng J , Jenner Katharine H , MacGregor Graham A
Published: November 2016

Objectives

To investigate the free sugars and calorie content of carbonated sugar-sweetened beverages (CSSB) available in the main UK supermarkets.

Study design

We carried out a cross-sectional survey in 2014 of 169 CSSB.

Methods

The free sugars (sugars g/100 mL) and calorie (kcal/100 mL) were collected from product packaging and nutrient information panels of CSSB available in 9 main UK supermarkets.

Results

The average free sugars content in CSSB was 30.1±10.7 g/330 mL, and 91% of CSSB would receive a ‘red’ (high) label for sugars per serving. There was a large variation in sugars content between different flavours of CSSB and within the same type of flavour ranging from 3.3 to 52.8 g/330 mL. On average, ginger beer (38.5±9.9 g/330 mL) contained the highest amounts of sugars and ginger ale (22.9±7.7 g/330 mL) contained the lowest. Cola flavour is the most popular flavour in the UK with an average free sugars content of 35.0±1.1 g/330 mL. On average, the supermarket own brand contained lower levels of sugars than branded products (27.9±10.6 vs 31.6±10.6 g/330 mL, p=0.02). The average calorie content in CSSB was 126.1±43.5 kcal/330 mL. Cola flavour had a calorie content of 143.5±5.2 kcal/330 mL. Among the 169 products surveyed, 55% exceeded the maximum daily recommendation for free sugars intake (30 g) per 330 mL.

Conclusions

Free sugars content of CSSB in the UK is high and is a major contributor to free sugars intake. There is a wide variation in the sugars content of CSSB and even within the same flavour of CSSB. These findings demonstrate that the amount of free sugars added to CSSB can be reduced without technical issues, and there is an urgent need to set incremental free sugars reduction targets. A reduction in sugars content and overall CSSB consumption will be very beneficial in reducing obesity, type 2 diabetes and dental caries.
Study on the efficiency of destress blasting in deep mine drift development
Authors: Sainoki Atsushi , Emad Muhammad Zaka , Mitri Hani S.
Published: November 2016

Canadian hard rock mines continue to reach deeper deposits, which poses greater challenges to mine safety including rock burst control. Destress blasting techniques have been successfully employed in such underground mines with the aim of preconditioning highly stressed rock mass to mitigate the risk for rock burst occurrence in deep mines. In the present study, the efficiency of destress blasting is examined through a comparison between traditional and alternative numerical modelling approaches. The traditional modelling approach assumes a uniformly distributed blast-induced damage zone extending over the entire drift face, whilst the alternative modelling approach, presented herein, simulates the damage zone for each individual blast hole. In the first part of this paper, a three-dimensional numerical model of a single blast hole is constructed, whereby the extent of blast-induced damage zone is delineated. The latter part of this paper uses the single-hole model results to examine the efficiency of destress blasting as practiced in drift development in deep mines. It is demonstrated through comparison of FLAC3D numerical simulation results that the traditional modelling approach may lead to an overly optimistic indication of destress blasting efficiency when compared with the alternative modelling approach, in which a more precise simulation of the damage zones is applied.
Acanthopanax senticosus: Photochemistry and Anticancer Potential
Authors: Li Ting , Ferns Kelsey , Yan Zi-Qiao , Yin Si-Yuan , Kou Jun-Jie , Li Dongsheng , Zeng Zheng , Yin Lin , Wang Xiaoyu , Bao Hong-Xia , Zhou Yu-Jie , Li Qing-Hai , Zhao Zhan-Yi , Liu Huidi , Liu Shu-Lin
Published: November 2016

Acanthopanax senticosus (previously classified as Eleutherococcus senticosus), commonly known as Ciwujia or Siberian Ginseng, is a traditional Chinese medicine (TCM), widely used for its high medicinal value, such as antifatigue, anti-inflammation, antistress, anti-ulcer and cardiovascular functions, in China, Korea, Japan and Russia. In the past decades, researchers worldwide have conducted systematic investigations on this herb, from chemistry to pharmacology, and a large number of chemical components have been characterized for their significant pharmacological effects. However, reports about the anticancer effects of this plant had been rare until recently, when considerable pharmacological experiments both in vitro and in vivo were conducted to study the anticancer effects of this herb. A. senticosus has been found to have inhibitory effects on malignant tumors, such as those in the lung and liver, suggesting that A. senticosus has potential to be developed as an effective anticancer drug. This paper reviews recent findings on the pharmacological properties of A. senticosus, with a focus on its anticancer effects.
Allergen-Removed Rhus verniciflua Extract Induces Ovarian Cancer Cell Death via JNK Activation
Authors: Kang Se-Hui , Hwang In-Hu , Son Eunju , Cho Chong-Kwan , Choi Jong-Soon , Park Soo-Jung , Jang Byeong-Churl , Lee Kyung-Bok , Lee Zee-Won , Lee Jong Hoon , Yoo Hwa-Seung , Jang Ik-Soon
Published: November 2016

Nuclear factor-[Formula: see text]B (NF-[Formula: see text]B)/Rel transcription factors are best known for their central roles in promoting cell survival in cancer. NF-[Formula: see text]B antagonizes tumor necrosis factor (TNF)-[Formula: see text]-induced apoptosis through a process involving attenuation of the c-Jun-N-terminal kinase (JNK). However, the role of JNK activation in apoptosis induced by negative regulation of NF-[Formula: see text]B is not completely understood. We found that allergen-removed Rhus verniciflua Stokes (aRVS) extract-mediated NF-[Formula: see text]B inhibition induces apoptosis in SKOV-3 ovarian cancer cells via the serial activation of caspases and SKOV-3 cells are most specifically suppressed by aRVS. Here, we show that in addition to activating caspases, aRVS extract negatively modulates the TNF-[Formula: see text]-mediated I[Formula: see text]B/NF-[Formula: see text]B pathway to promote JNK activation, which results in apoptosis. When the cytokine TNF-[Formula: see text] binds to the TNF receptor, I[Formula: see text]B dissociates from NF-[Formula: see text]B. As a result, the active NF-[Formula: see text]B translocates to the nucleus. aRVS extract (0.5[Formula: see text]mg/ml) clearly prevented NF-[Formula: see text]B from mobilizing to the nucleus, resulting in the upregulation of JNK phosphorylation. This subsequently increased Bax activation, leading to marked aRVS-induced apoptosis, whereas the JNK inhibitor SP600125 in aRVS extract treated SKOV-3 cells strongly inhibited Bax. Bax subfamily proteins induced apoptosis through caspase-3. Thus, these results indicate that aRVS extract contains components that inhibit NF-[Formula: see text]B signaling to upregulate JNK activation in ovarian cancer cells and support the potential of aRVS as a therapeutic agent for ovarian cancer.
Ab initio study of optical and vibrational properties of Ni3C
Authors: Golivand Mohammad Bagher , Boochani Arash , Akhtar Arsalan , Torkashvand Maryam , Karimian Nashmyl
Published: November 2016

The structural, electronic, optical and vibrational properties of Ni3C have been studied by density functional theory (DFT) framework with first-principles study. The obtained structural parameters are in good agreement with other works. The electronic study demonstrates metallic behavior of Ni3C since it has no energy gap at Fermi level. The optical parameters such as real and imaginary dielectric functions, loss function, conductivity, reflection, refraction indexes and absorption coefficients are studied. The phonon investigations confirm that the Ni3C bulk is dynamically stable and carbon has a major role in optical spectrum of the material at infrared region. Finally, the [Formula: see text] behavior of [Formula: see text] at low temperatures is obtained, as expected.
Excellent low-frequency sound absorption of radial membrane acoustic metamaterial
Authors: Gao Nansha , Wu Jiu Hui , Hou Hong , Yu Lie
Published: November 2016

This paper proposes a new radial membrane acoustic metamaterial (RMAM) structure, wherein a layer membrane substrate is covered with a rigid ring (polymethyl methacrylate frame and aluminum lump). The dispersion relationships, transmission spectra and displacement fields of the eigenmodes of this radial membrane acoustic metamaterial are studied with FEM. In contrast to the traditional radial phononic crystals (RPCs), the proposed structures can open bandgaps (BGs) in lower frequency range (0–300 Hz). Simulation results show that the physical mechanism behind the bandgaps is the coupling effects between the rotational vibration of aluminum lump and the transverse vibration of membrane. Geometrical parameters which can adjust the bandgaps’ widths or positions are analyzed. Finally, we investigate the axial sound transmission loss of this acoustic metamaterial structure, and discuss the effects of factor loss, membrane thickness and the number of layers of unit cell on the axial sound transmission loss. Dynamic effective density proves the accuracy of the FEM results. This kind of structure has potential application in pipe or circular ring structure for damping/noise reduction.
Production of nearly monodisperse Fe3O4 and Fe@Fe3O4 nanoparticles in aqueous medium and their surface modification for biomedical applications
Authors: Tegafaw Tirusew , Xu Wenlong , Lee Sang Hyup , Chae Kwon Seok , Chang Yongmin , Lee Gang Ho
Published: November 2016

Iron (Fe)-based nanoparticles are extremely valuable in biomedical applications owing to their low toxicity and high magnetization values at room temperature. In this study, we synthesized nearly monodisperse iron oxide (Fe3O4) and Fe@Fe3O4 (core: Fe, shell: Fe3O[Formula: see text] nanoparticles in aqueous medium under argon flow and then, coated them with various biocompatible ligands and silica. In this study, eight types of surface-modified nanoparticles were investigated, namely, Fe3O4@PAA (PAA = polyacrylic acid; [Formula: see text] of PAA = 5100 amu and 15,000 amu), Fe3O4@PAA–FA (FA = folic acid; [Formula: see text] of PAA = 5100 amu and 15,000 amu), Fe3O4@PEI–fluorescein (PEI = polyethylenimine; [Formula: see text] of PEI = 1300 amu), Fe@Fe3O4@PEI ([Formula: see text] of PEI = 10,000 amu), Fe3O4@SiO2 and Fe@Fe3O4@SiO2 nanoparticles. We characterized the prepared surface-modified nanoparticles using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) absorption spectroscopy, a superconducting quantum interference device (SQUID), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and confocal microscopy. Finally, we measured the cytotoxicity of the samples. The results indicate that the surface-modified nanoparticles are biocompatible and are potential candidates for various biomedical applications.
Morphological, thermal and optical studies of jute-reinforced PbSrCaCuO–polypropylene composite
Authors: Jacob Reenu , Isac Jayakumari
Published: November 2016

New research with modern technologies has always grabbed substantial attention. Conservation of raw materials like natural fibers has helped composite world to explore eco-friendly components. The aim of this paper is to study the potential of jute fiber-reinforced ceramic polymers. Alkali-treated jute fiber has been incorporated in a polypropylene ceramic matrix at different volume fractions. The morphological, thermal and optical studies of jute-reinforced ceramic Pb2Sr2CaCu2O9 (PbSrCaCuO) are studied. Morphological results evidently demonstrate that when the polypropylene ceramic matrix is reinforced with jute fiber, interfacial interaction between the varying proportions of the jute fiber and ceramic composite takes place. TGA and DSC results confirm the enhancement in the thermal stability of ceramic composites reinforced with jute fiber. The UV analysis of the composite gives a good quality measure on the optical properties of the new composite prepared.
Two kinds of finite-dimensional integrable reduction to the Harry–Dym hierarchy
Authors: Chen Jinbing
Published: November 2016

In this paper, two kinds of finite-dimensional integrable reduction are studied for the Harry–Dym (HD) hierarchy. From the nonlinearization of Lax pair, the HD hierarchy is reduced to a class of finite-dimensional Hamiltonian systems (FDHSs) in view of a Bargmann map and a set of Neumann type systems by a Neumann map, which separate temporal and spatial variables on the symplectic space [Formula: see text] and the tangent bundle of ellipsoid [Formula: see text], respectively. It turns out that involutive solutions of the resulted finite-dimensional integrable systems (FDISs) directly give rise to finite parametric solutions of HD hierarchy through the Bargmann and Neumann maps. The finite-gap potential to the high-order stationary HD equation is obtained that cuts out a finite-dimensional invariant subspace for the HD flows. Finally, some comparisons of two kinds of integrable reductions are then discussed.
Particle entropy and depairing in hot nuclei
Authors: Saranya J. Dhivya , Boomadevi N. , Rajasekaran T. R.
Published: November 2016

The nuclear level densities and single particle entropies are predicted for nuclei in the mass region [Formula: see text] within a framework of statistical theory of hot nuclei method. In this method, particle-number and energy conservation as well as nuclear pairing correlations are included in the partition function of grand canonical ensemble. The suppression of pairing correlations is distinctly noticed in temperature dependence of entropies between the critical temperatures [Formula: see text] MeV and [Formula: see text] MeV for [Formula: see text], [Formula: see text] and [Formula: see text] isotopes of the elements. These structural thermodynamic entropies are interpreted as a remarkable signature of the superfluid to normal phase transition connected to the vanishing of pairing gap. The calculated level densities are compared with recent experimental values. In addition, the single particle entropy of intermediate-mass nuclei is depicted as half of the entropy of mid-shell nuclei in the rare-earth region. As a consequence, the [Formula: see text] shell closure of [Formula: see text]V carries low entropy at low excitation energy presents an interesting analogy to the [Formula: see text] shell closure of [Formula: see text]Ni. Merely, in the case of odd–even [Formula: see text] has higher entropy than the even–even [Formula: see text] nucleus.
Noise Equivalent Power of Graphene–Superconductor-Based Optical Sensor
Authors: Aghda B. Afkhami , Moftakharzadeh A. , Hosseini M.
Published: November 2016

In this paper, the noise equivalent power (NEP) of optical sensors based on graphene–superconductor junctions in the voltage bias operation mode has been calculated. The effects of device parameters such as temperature, magnetic field and device resistance on the NEP of these detectors have been thoroughly investigated. By solving the related equations, graphene specific heat, thermal conductivity, electron–phonon interaction and responsivity of the detector have been obtained. Using the calculated parameters, the NEP of the device was obtained. The results show that at constant magnetic field the NEP will increase linearly by increasing device temperature. On the other hand, at constant temperature the behavior of NEP versus magnetic field is first increasing and then decreasing. Our calculations show that the optimal resistance of the device has a direct relation with respect to the device temperature, while in the investigated operating range the optimal resistance of device is almost independent of the magnetic field.
Central automorphisms of free nilpotent Lie algebras
Authors: Öztekin Özge , Ekici Naime
Published: November 2016

Let [Formula: see text] be the free nilpotent Lie algebra of finite rank [Formula: see text] [Formula: see text] and nilpotency class [Formula: see text] over a field of characteristic zero. We give a characterization of central automorphisms of [Formula: see text] and we find sufficient conditions for an automorphism of [Formula: see text] to be a central automorphism.
Pretreated Lignocellulosic Waste Mediated Biosynthesis of Silver Nanoparticles Under Room Temperature
Authors: Manjamadha V. P. , Muthukumar Karuppan
Published: November 2016

The current work elucidates the utilization of biowaste as a valuable reducing agent for the synthesis of silver nanoparticles. In this study, the wastewater generated during the alkaline pretreatment of lignocellulosic wastes (APLW) was used as a bioreductant to reduce silver nitrate under room temperature. Synthesis of stable silver nanoparticles (AgNPs) was achieved rapidly on addition of APLW into the silver nitrate solution (1[Formula: see text]mM). The morphological characterization of AgNPs was performed using field emission scanning electron microscopy (FESEM). The micrograph clearly depicted the presence of spherical AgNPs. The presence of elemental silver along with biomoilties was determined using energy dispersive X-ray spectroscopy (EDAX) analysis. The X-ray diffraction (XRD) study proved the crystalline form of stable AgNPs. The AgNPs exhibited excellent antibacterial performance against Gram negative organism. The immediate bioreduction of silver ions using APLW was well illustrated in the present study. Thus, APLW serve as an alternative source for reducing agents instead of utilizing valuable medicinal plants for nanoparticles synthesis.
Synthesis of Cu Loaded TiO2 Nanoparticles for the Improved Photocatalytic Degradation of Rhodamine B
Authors: Kavitha V. , Ramesh P. S. , Geetha D.
Published: November 2016

Copper doped Titanium dioxide TiO2 nanoparticles were synthesized by sol–gel method using titanium tetraisopropoxide and copper sulfate as precursors. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), Photoluminesce spectroscopy (PL) and atomic force microscopy (AFM). XRD analysis confirms the formation of anatase titanium dioxide and average particle size was 35[Formula: see text]nm. Cu– TiO2 exhibits a shift in the absorption edge toward visible spectrum. The rate of recombination and transfer behavior of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. From SEM spherical shaped nanoparticles was observed. Comparing with pure TiO2 nanoparticles, Cu doped TiO2 photocatalyst exhibited enhanced photocatalytic activity under natural sunlight irradiation in the decomposition of rhodamine B aqueous solution. The maximum 97% of degradation efficiency of Rhodamine B was observed at 0.6% Cu–TiO2 within 180[Formula: see text]min. The photocatalytic efficiency of Rhodamine B of Cu doped TiO2 nanoparticle was higher than the pure TiO2, which could be attributed to the small crystallinity intense light absorption in Sunlight and narrow bandgap energy of Copper.
Electrical Transport Properties of Carbon Nanotube Metal-Semiconductor Heterojunction
Authors: Talukdar Keka , Shantappa Anil
Published: November 2016

Carbon nanotubes (CNTs) have been proved to have promising applicability in various fields of science and technology. Their fascinating mechanical, electrical, thermal, optical properties have caught the attention of today’s world. We have discussed here the great possibility of using CNTs in electronic devices. CNTs can be both metallic and semiconducting depending on their chirality. When two CNTs of different chirality are joined together via topological defects, they may acquire rectifying diode property. We have joined two tubes of different chiralities through circumferential Stone–Wales defects and calculated their density of states by nearest neighbor tight binding approximation. Transmission function is also calculated to analyze whether the junctions can be used as electronic devices. Different heterojunctions are modeled and analyzed in this study. Internal stresses in the heterojunctions are also calculated by molecular dynamics simulation.
Studies of Silicon Nanowires with Different Parameters — By PECVD
Authors: Leela S. , Abirami T. , Bhattacharya Sekhar , Ahmed Nafis , Monika S. , Priya R. Nivedha
Published: November 2016

One-dimensional nanostructures such as nanowires have a wide range of applications. Silicon is the best competitive material for the carbon nanotubes (CNTs). Carbon and silicon have some similar and peculiar properties. Silicon nanowires (SiNWs) were synthesized using plasma enhanced chemical vapor deposition (PECVD) on p-Si (111) wafer. Gold is used as a catalyst for the growth of the SiNWs. Based on our fundamental understanding of vapor–liquid–solid (VLS) nanowire growth mechanism, different levels of growth controls have been achieved. Gold catalyst deposited and annealed at different temperatures with different thicknesses (450[Formula: see text]C, 500[Formula: see text]C and 550[Formula: see text]C, 600[Formula: see text]C, 650[Formula: see text]C for 4[Formula: see text]min and 8[Formula: see text]min and 3[Formula: see text]nm, 5[Formula: see text]nm, 30[Formula: see text]nm Au thickness). SiNW grown by PECVD with different carrier gases varies with flow rate. We observed the different dimensions of Si nanowires by FESEM and optimized the growth parameters to get the vertical aligned and singular Si nanowires. Optical phonon of the Si nanowires and crystallinity nature were identified by Raman spectral studies.
Synthesis of Gold Nanoparticles Using Garcinia Indica Fruit Rind Extract
Authors: Krishnaprabha M. , Pattabi Manjunatha
Published: November 2016

This report presents the easily reproducible biosynthesis of gold nanoparticles (AuNPs) at room temperature with extract prepared using three year old dried Garcinia Indica (GI) fruit rind. Due to the presence of two major bioactive compounds garcinol and hydroxy citric acid, rinds of GI fruit exhibit anti-cancer and anti-obesity properties. The quantity of fruit rind extract directed the morphology of the as synthesized particles. The nucleation and growth of AuNPs and catalytic activity are studied using UV-Vis spectroscopy. The crystalline nature of biosynthesized AuNPs is corroborated by X-ray Diffraction techniques. The morphology is studied using field emission scanning electron microscopy (FESEM). Fourier transform infra-red (FTIR) spectroscopy analysis revealed that biomolecules were involved in the synthesis and capping of AuNPs. As the Fermi potential of noble metal NPs becomes more negative, they are used in various electron transfer processes. The AuNPs produced using GI extract showed excellent catalytic activity when used as a catalyst in the reduction of well-known toxic pollutant 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP) in the presence of excess sodium borohydride.
Peaks, Slopes, Canyons and Plateaus: Identifying Technology Trends Throughout the Life Cycle
Authors: Efimenko Irina V. , Khoroshevsky Vladimir F.
Published: November 2016

A novel domain-independent approach to technology trend monitoring is presented in the paper. It is based on the ontology of a technology trend, hype cycles methodology, and semantic indicators which provide evidence of a maturity level of a technology. This approach forms the basis for implementation of text-mining software tools. Algorithms behind these tools allow users to escape from getting too general or garbage results which make it impossible to identify promising technologies at early stages (early detection, weak signals). Besides, these algorithms provide high-quality results in extraction of complex multiword terms which correspond to technological concepts forming a trend. Methodology and software developed as a result of this study are applicable to various industries with minor adjustments and require no deep expert knowledge from a user.
Dietary gossypol suppressed postprandial TOR signaling and elevated ER stress pathways in turbot (Scophthalmus maximus L.)
Authors: Bian Fuyun , Jiang Haowen , Man Mingsan , Mai Kangsen , Zhou Huihui , Xu Wei , He Gen
Published: November 2016

Gossypol is known to be a polyphenolic compound toxic to animals. However, its molecular targets are far from fully characterized. To evaluate the physiological and molecular effects of gossypol, we chose turbot ( Scophthalmus maximus L.), a carnivorous fish, as our model species. Juvenile turbots (7.83 ± 0.02 g) were fed diets containing gradient levels of gossypol at 0 (G0), 600 (G1), and 1,200 (G2) mg/kg diets for 11 wk. After the feeding trial, fish growth, body protein, and fat contents were significantly reduced in the G2 group compared with those of the G0 group ( P < 0.05). Gossypol had little impact on digestive enzyme activities and intestine morphology. However, gossypol caused liver fibrosis and stimulated chemokine and proinflammatory cytokine secretions. More importantly, gossypol suppressed target of rapamycin (TOR) signaling and induced endoplasmic reticulum (ER) stress pathway in both the feeding experiment and cell cultures. Our results demonstrated that gossypol inhibited TOR signaling and elevated ER stress pathways both in vivo and in vitro, thus providing new mechanism of action of gossypol in nutritional physiology.