Plant N-glycan breakdown by human gut Bacteroides.

The major nutrients available to the human colonic microbiota are complex glycans derived from the diet. To degrade this highly variable mix of sugar structures, gut microbes have acquired a huge array of different carbohydrate-active enzymes (CAZymes), predominantly glycoside hydrolases, many of which have specificities that can be exploited for a range of different applications. Plant N-glycans are prevalent on proteins produced by plants and thus components of the diet, but the breakdown of these complex molecules by the gut microbiota has not been explored. Plant N-glycans are also well characterized allergens in pollen and some plant-based foods, and when plants are used in heterologous protein production for medical applications, the N-glycans present can pose a risk to therapeutic function and stability. Here we use a novel genome association approach for enzyme discovery to identify a breakdown pathway for plant complex N-glycans encoded by a gut Bacteroides species and biochemically characterize five CAZymes involved, including structures of the PNGase and GH92 α-mannosidase. These enzymes provide a toolbox for the modification of plant N-glycans for a range of potential applications. Furthermore, the keystone PNGase also has activity against insect-type N-glycans, which we discuss from the perspective of insects as a nutrient source.

Transcriptomic analysis of tuberous root in two sweet potato varieties reveals the important genes and regulatory pathways in tuberous root development.

BACKGROUND: Tuberous root formation and development is a complex process in sweet potato, which is regulated by multiple genes and environmental factors. However, the regulatory mechanism of tuberous root development is unclear. RESULTS: In this study, the transcriptome of fibrous roots (R0) and tuberous roots in three developmental stages (Rl, R2, R3) were analyzed in two sweet potato varieties, GJS-8 and XGH. A total of 22,914 and 24,446 differentially expressed genes (DEGs) were identified in GJS-8 and XGH respectively, 15,920 differential genes were shared by GJS-8 and XGH. KEGG pathway enrichment analysis showed that the DEGs shared by GJS-8 and XGH were mainly involved in "plant hormone signal transduction" "starch and sucrose metabolism" and "MAPK signal transduction". Trihelix transcription factor (Tai6.25300) was found to be closely related to tuberous root enlargement by the comprehensive analysis of these DEGs and weighted gene co-expression network analysis (WGCNA). CONCLUSION: A hypothetical model of genetic regulatory network for tuberous root development of sweet potato is proposed, which emphasizes that some specific signal transduction pathways like "plant hormone signal transduction" "Ca2+signal" "MAPK signal transduction" and metabolic processes including "starch and sucrose metabolism" and "cell cycle and cell wall metabolism" are related to tuberous root development in sweet potato. These results provide new insights into the molecular mechanism of tuberous root development in sweet potato.

Algoriphagus pacificus sp. nov. and Algoriphagus oliviformis sp. nov., isolated from a mariculture fishpond.

Two Gram-stain-negative, catalase-positive, oxidase-negative, rod-shaped, non-flagellated, non-spore-forming and non-motile strains (YJ13CT and H41T) were isolated from a mariculture fishpond in PR China. Comparisons based on 16S rRNA gene sequences indicated that YJ13CT and H41T shared 16S rRNA gene sequences similarities between 92.6 and 99.2 % with species of the genus Algoriphagus. YJ13CT only shared 93.8 % 16S rRNA gene sequence similarity with H41T. The reconstructed phylogenetic and phylogenomic trees indicated that YJ13CT and H41T clustered closely with species of the genus Algoriphagus. The calculated pairwise orthologous average nucleotide identity with usearch (OrthoANIu) values between strains YJ13CT and H41T and other related strains were all less than 79.5 %. The OrthoANIu value between YJ13CT and H41T was only 69.9 %. MK-7 was the predominant respiratory quinone of YJ13CT and H41T and their major cellular fatty acids contained iso-C15 : 0, C16 : 1 ω7c and C17 : 1 ω9c. The polar lipids profiles of YJ13CT and H41T consisted of phosphatidylethanolamine and several kinds of unidentified lipids. Combining the above descriptions, strains YJ13CT and H41T represent two distinct novel species of the genus Algoriphagus, for which the names Algoriphagus pacificus sp. nov. (type strain YJ13CT=GDMCC 1.2178T=KCTC 82450T) and Algoriphagus oliviformis sp. nov. (type strain H41T=GDMCC 1.2179T=KCTC 82451T) are proposed.

Bowmanella yangjiangensis sp. nov. and Amphritea pacifica sp. nov., isolated from mariculture fishponds in China.

Four Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and motile strains (Y26, Y57T, ZJ14WT and RP18W) were isolated from mariculture fishponds in PR China. Comparisons based on 16S rRNA gene sequences showed that strains Y26 and Y57T share 16S rRNA gene sequence similarities in the range of 95.1-98.5 % with species of the genus Bowmanella, and strains ZJ14WT and RP18W share 16S rRNA gene sequence similarities in the range of 96.7 -98.8 % with species of the genus Amphritea, respectively. The genome sizes of strains Y26, Y57T, ZJ14WT and RP18W were about 4.85, 5.40, 4.70 and 4.70 Mbp with 49.5, 51.7, 51.2 and 51.3 mol% G+C content, respectively. The calculated pairwise OrthoANIu values among strains Y26, Y57T and species of the genus Bowmanella were in the range of 72.6-83.1 %, but the value between strains Y26 and Y57T was 96.2 %. The pairwise OrthoANIu values among strains ZJ14WT, RP18W and other species of the genus Amphritea were all less than 93.9 %, but the value between strains ZJ14WT and RP18W was 99.3 %. Q-8 was the major respiratory quinone of strains Y26, Y57T, ZJ14WT and RP18W, and the major fatty acids of these strains were all C16 : 1 ω7c, C16 : 0 and C18 : 1 ω7c. The predominant polar lipids of strains Y26 and Y57T included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol, but strains ZJ14WT and RP18W only contained phosphatidylethanolamine and phosphatidylglycerol. Combining phenotypic, biochemical and genotypic characteristics, strains Y26 and Y57T should belong to the same species and represent a novel member of the genus Bowmanella, and strains ZJ14WT and RP18W should belong to the same species and represent a novel member of the genus Amphritea, for which the names Bowmanella yangjiangensis sp. nov. (type strain Y57T=GDMCC 1.2180T=KCTC 82439T) and Amphritea pacifica sp. nov. (type strain ZJ14WT=GDMCC 1.2203T=KCTC 82438T) are proposed.

Enhanced Electrochemical Performance of Aprotic Li-CO2 Batteries with a Ruthenium-Complex-Based Mobile Catalyst.

Li-CO2 batteries are regarded as next-generation high-energy-density electrochemical devices. However, the greatest challenge arises from the formation of the discharge product, Li2 CO3 , which would accumulate and deactivate heterogenous catalysts to cause huge polarization. Herein, Ru(bpy)3 Cl2 was employed as a solution-phase catalyst for Li-CO2 batteries and proved to be the most effective one screened so far. Spectroscopy and electrochemical analyses elucidate that the RuII center could interact with both CO2 and amorphous Li2 C2 O4 intermediate, thus promoting electroreduction process and delaying carbonate transformation. As a result, the charge potential is reduced to 3.86 V and over 60 discharge/charge cycles are achieved with a fixed capacity of 1000 mAh g-1 at a current density of 300 mA g-1 . Our work provides a new avenue to improve the electrochemical performance of Li-CO2 batteries with efficient mobile catalysts.

Janthinobacterium violaceinigrum sp. nov., Janthinobacterium aquaticum sp. nov. and Janthinobacterium rivuli sp. nov., isolated from a subtropical stream in China.

Four strains assigned the names FT13WT, FT14W, FT58WT and FT68WT were isolated from a subtropical stream in PR China. All the strains were Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and motile with flagella. Comparisons based on 16S rRNA gene sequences showed that strains FT13WT, FT14W, FT58WT and FT68WT belonged to genus Janthinobacterium and shared 16S rRNA gene similarities in the range of 98.8-99.7 % with Janthinobacterium lividum DSM 1522T, Janthinobacterium agaricidamnosum DSM 9628T and 'Janthinobacterium svalbardensis JA-1', respectively. The calculated pairwise average nucleotide identity (ANI) values among the genomes of above seven strains were in the range of 79.0-92.2 %, except that the ANI value was 96.8 % between strain FT13WT and FT14W. The respiratory quinone of strains FT13WT, FT14W, FT58WT and FT68WT was determined to be Q-8. The major fatty acids were C16 : 1 ω7c, C16 : 0, C18 : 1 ω7c and C12 : 0. The polar lipids included phosphatidylethanolamine, phosphatidylglycerol and one unidentified phospholipid. The genome sizes of strains FT13WT, FT14W, FT58WT and FT68WT were 6.45, 6.38, 5.73 and 6.37 Mbp with G+C contents of 63.4, 63.7, 61.6 and 63.1 mol%, respectively. Combining phenotypic, biochemical, genotypic and ANI data, strain FT13WT and FT14W should belong to the same species. The four strains were considered to represent three novel species within genus Janthinobacterium, for which the names Janthinobacterium violaceinigrum sp. nov. (type strain FT13WT=GDMCC 1.1638T=KACC 21319T), Janthinobacterium aquaticum sp. nov. (FT58WT=GDMCC 1.1676T=KACC 21468T) and Janthinobacterium rivuli sp. nov. (FT68WT=GDMCC 1.1677T=KACC 21469T) are proposed.

Correction to: Duganella rivus sp. nov., Duganella fentianensis sp. nov., Duganella qianjiadongensis sp. nov. and Massilia guangdongensis sp. nov., isolated from subtropical streams in China and reclassification of all species within genus Pseudoduganella.

In the published version of the article, the title should have read 'Duganella rivi sp. nov., Duganella fentianensis sp. nov., Duganella qianjiadongensis sp. nov. and Massilia guangdongensis sp. nov., isolated from subtropical streams in China and reclassification of all species within genus Pseudoduganella'.

Duganella rivus sp. nov., Duganella fentianensis sp. nov., Duganella qianjiadongensis sp. nov. and Massilia guangdongensis sp. nov., isolated from subtropical streams in China and reclassification of all species within genus Pseudoduganella.

Four Gram-stain-negative, catalase-positive, rod-shaped and motile strains (FT55WT, FT93WT, CY13WT and DS3T) were isolated from subtropical streams in China. Comparisons based on 16S rRNA gene sequences indicated that strains FT55WT, FT93WT and CY13WT take strain Pseudoduganella danionis E3/2T, and strain DS3T takes strain Pseudoduganella eburnea 10R5-21T as their closest neighbour, respectively. The genome sizes of strains FT55WT, FT93WT, CY13WT and DS3T were 6.15, 5.10, 5.31 and 5.72 Mbp with G+C contents of 61.7, 60.9, 60.6 and 64.0%, respectively. The reconstructed phylogenomic tree based on concatenated 92 core genes showed that strain FT55WT clusters closely with Duganella radicis KCTC 22382T and Duganella sacchari Sac-22T, strains FT93WT and CY13WT form a distinct clade with P. danionis DSM 103461T and this clade clusters with the clades of genus Duganella together, and strain DS3T forms a distinct clade with P. eburnea JCM 31587T and Pseudoduganella violaceinigra DSM 15887T and this clade clusters closely with the clades of genus Massilia, respectively. The calculated pairwise OrthoANIu values and digital DNA-DNA hybridization (DDH) values among strains FT55WT, FT93WT, CY13WT, DS3T and related strains were in the ranges of 75.6-94.2% and 20.6-56.2%, respectively. Q-8 was the sole respiratory quinone of these four strains. The major fatty acids were C16:1ω7c, C16:0 and C12:0. The polar lipids included phosphatidylglycerol, phosphatidylethanolamine and one unidentified phospholipid. Considering the similar fatty acids and polar lipids profiles of species within genus Pseudoduganella, Massilia and Duganella, there is currently no justification for assigning the species of genus Pseudoduganella into the Massilia and Duganella clades in the phylogenomic tree. It is reasonable to transfer P. violaceinigra and P. eburnea to the genus Massilia as Massilia violaceinigrum comb. nov. and Massilia eburnea comb. nov., and transfer P. danionis to the genus Duganella as Duganella danionis comb. nov. Considering phylogenomic analysis, OrthoANIu data, digital DDH data and a range of physiological and biochemical characteristics, strains FT55WT, FT93WT and CY13WT should be assigned to genus Duganella, and strain DS3T should be classified as a novel species within genus Massilia, for which the names Duganella rivus sp. nov. (type strain FT55WT = GDMCC 1.1675T = KACC 21467T), Duganella fentianensis sp. nov. (type strain FT93WT = GDMCC 1.1683T = KACC 21475T), Duganella qianjiadongensis sp. nov. (type strain CY13WT = GDMCC 1.1669T = KACC 21461T) and Massilia guangdongensis sp. nov. (type strain DS3T = GDMCC 1.1636T = KACC 21312T) are proposed.

Reactive oxygen species regulate miR-17-5p expression via DNA methylation in paraquat-induced nerve cell damage.

There is emerging evidence suggesting that oxidative stress and DNA methylation can alter miRNA expression. However, little is known on the mechanism of miR-17-5p expression changes in paraquat (PQ)-induced nerve cell damage. In the present study, neuro-2a cells were pretreated with antioxidant N-acetylcysteine (NAC) or DNA methylation inhibitor decitabine (DAC), then exposed to different concentrations of PQ, while the expression levels of miR-17-5p were detected by qRT-PCR. Here, it is showed that PQ downregulated the expression of miR-17-5p dose-dependently in neuro-2a cells. The DNA methylation level was upregulated after PQ exposure, while downregulated with the pretreatment of NAC in the above content, detected by 5-mC immunofluorescence technique. The interaction effect of NAC and PQ in alternating DNA methylation level was further confirmed by flow cytometry. NAC and DAC individually had an interaction effect in PQ-induced nerve cell damage. After using NAC, PQ-induced ROS elevation and DNA methylation are reduced, thereby preventing the proapoptotic effect of miR-17-5p. Above all, PQ can induce DNA methylation variations through ROS production, leading to the downregulation of miR-17-5p expression in PQ-induced nerve cell damage.

New Insights into Porcine Milk N-Glycome and the Potential Relation with Offspring Gut Microbiome.

N-Glycans are an important source of milk oligosaccharides. In addition to free oligosaccharides found in milk, N-glycans can also be utilized by gut microbes. A potential for milk N-glycans to act as gut microbe regulators in suckling animals has attracted considerable attention; however, sow milk N-glycans and their potential effects upon the piglet's gut microbes in vivo remain unknown. In the present study, we profiled the milk N-glycans of Meishan and Yorkshire sows during lactation using UPLC and a mass spectrometry-based glycome method, and we explored the correlations between milk N-glycans and offspring gut microbiota. Twenty-two N-glycan structures were identified in sow milk, among which 36% (8 out of 22) were fucosylated, 41% (9 out of 22) were sialylated, and 14% (3 out of 22) were high mannosylated. An N-glycan with a NeuGc structure (namely PNO20, GlcNAc4-Man3-Gal2-Fuc-Neu5Gc) was identified in sow milk for the first time. No compositional differences between the two breeds or between different lactation times were found in porcine milk N-linked oligosaccharides (PNOs); however, the abundances of different structures within this class did vary. The relative abundances of fucosylated PNO3 (GlcNAc4-Man3-Fuc) and sialylated PNO18 (GlcNAc4-Man3-Gal2-NeuAc) increased during lactation, and Meishan sows demonstrated a higher ( P < 0.05) abundance of mannosylated PNO10 (GlcNAc2-Man6) and sialylated PNO17 (GlcNAc5-Man3-Gal-NeuAc) than Yorkshire sows. Apparent correlations between milk N-glycans and offspring gut microbial populations were found; for example, mannosylated PNO21 (GlcNAc2-Man9) was positively correlated with OTU706 ( Lactobacillus amylovorus) and OTU1380 ( Bacteroides uniformis). Overall, our results indicate that the milk N-glycome of Meishan and Yorkshire sows differs in N-glycome characteristics and that this is correlated to abundances of certain piglet gut microbes. These findings provide a reference for future elucidation of the involvement of gut microbes in milk N-glycan metabolism, which is important to the health both of large domestic animals and humans.

Characterization of Stackebrandtia nassauensis GH 20 Beta-Hexosaminidase, a Versatile Biocatalyst for Chitobiose Degradation.

An unstudied ß-N-acetylhexosaminidase (SnHex) from the soil bacterium Stackebrandtia nassauensis was successfully cloned and subsequently expressed as a soluble protein in Escherichia coli. Activity tests and the biochemical characterization of the purified protein revealed an optimum pH of 6.0 and a robust thermal stability at 50 °C within 24 h. The addition of urea (1 M) or sodium dodecyl sulfate (1% w/v) reduced the activity of the enzyme by 44% and 58%, respectively, whereas the addition of divalent metal ions had no effect on the enzymatic activity. PUGNAc (O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate) strongly inhibited the enzyme in sub-micromolar concentrations. The ß-N-acetylhexosaminidase was able to hydrolyze ß1,2-linked, ß1,3-linked, ß1,4-linked, and ß1,6-linked GlcNAc residues from the non-reducing end of various tested glycan standards, including bisecting GlcNAc from one of the tested hybrid-type N-glycan substrates. A mutational study revealed that the amino acids D306 and E307 bear the catalytically relevant side acid/base side chains. When coupled with a chitinase, the ß-N-acetylhexosaminidase was able to generate GlcNAc directly from colloidal chitin, which showed the potential of this enzyme for biotechnological applications.

Cloning, purification and biochemical characterisation of a GH35 beta-1,3/beta-1,6-galactosidase from the mucin-degrading gut bacterium Akkermansia muciniphila.

A putative GH35 ß-galactosidase gene from the mucin-degrading bacterium Akkermansia muciniphila was successfully cloned and further investigated. The recombinant enzyme with the molecular mass of 74 kDa was purified to homogeneity and biochemically characterised. The optimum temperature of the enzyme was 42 °C, and the optimum pH was determined to be pH 3.5. The addition of sodium dodecyl sulphate (SDS) reduced the enzyme's activity significantly. The addition of Mg2+-ions decreased the activity of the ß-galactosidase, whereas other metal ions or EDTA showed no inhibitory effect. The enzyme catalysed the hydrolysis of ß1,3- and ß1,6- linked galactose residues from various substrates, whereas only negligible amounts of ß1,4-galactose were hydrolysed. The present study describes the first functional characterisation of a ß-galactosidase from this human gut symbiont.

UDP-Glucose 4-Epimerase and ß-1,4-Galactosyltransferase from the Oyster Magallana gigas as Valuable Biocatalysts for the Production of Galactosylated Products.

Uridine diphosphate galactose (UDP-galactose) is a valuable building block in the enzymatic synthesis of galactose-containing glycoconjugates. UDP-glucose 4-epimerase (UGE) is an enzyme which catalyzes the reversible conversion of abundantly available UDP-glucose to UDP-galactose. Herein, we described the cloning, expression, purification, and biochemical characterization of an unstudied UGE from the oyster Magallana gigas (MgUGE). Activity tests of recombinantly expressed MgUGE, using HPLC (high-performance liquid chromatography), mass spectrometry, and photometric assays, showed an optimal temperature of 16 °C, and reasonable thermal stability up to 37 °C. No metal ions were required for enzymatic activity. The simple nickel-affinity-purification procedure makes MgUGE a valuable biocatalyst for the synthesis of UDP-galactose from UDP-glucose. The biosynthetic potential of MgUGE was further exemplified in a coupled enzymatic reaction with an oyster-derived ß-1,4-galactosyltransferase (MgGalT7), allowing the galactosylation of the model substrate para-nitrophenol xylose (pNP-xylose) using UDP-glucose as the starting material.

Novel reassortant H9N2 viruses in pigeons and evidence for antigenic diversity of H9N2 viruses isolated from quails in Egypt.

The endemicity of avian influenza viruses (AIVs) among Egyptian poultry represents a public health risk. Co-circulation of low pathogenic AIV H9N2 subtype with highly pathogenic AIV H5N1 subtype in Egyptian farms provides a possibility to generate novel reassortant viruses. Here, the genetic characteristics of surface glycoproteins of 59 Egyptian H9N2 viruses, isolated between 2013 and 2015, were analysed. To elucidate the potential of genetic reassortment, 10 H9N2 isolates were selected based on different avian hosts (chickens, ducks, pigeons and quails) and phylogenetic analyses of their full genome sequences were conducted. Additionally, we performed antigenic analysis to further investigate the antigenic evolution of H9N2 viruses isolated during 2011-2015. Different viral characteristics including receptor-binding affinity and drug resistance of representative Egyptian H9N2 viruses were further investigated. The surface glycoproteins of current Egyptian H9N2 viruses were closely related to viruses of the G1-like lineage isolated from Egypt. Several genetic markers that enhance virulence in poultry and transmission to humans were detected. Analysis of the full genome of 10 H9N2 isolates indicated that two pigeon isolates inherited five internal genes from Eurasian AIVs circulating in wild birds. Antigenic conservation of different Egyptian H9N2 isolates from chickens, pigeons and ducks was observed, whereas quail isolates showed antigenic drift. The Egyptian H9N2 viruses preferentially bound to the human-like receptor rather than to the avian-like receptor. Our results suggest that the endemic H9N2 viruses in Egypt contain elements that may favour avian-to-human transmission and thus represent a public health risk.

Approximate Sensory Data Collection: A Survey.

With the rapid development of the Internet of Things (IoTs), wireless sensor networks (WSNs) and related techniques, the amount of sensory data manifests an explosive growth. In some applications of IoTs and WSNs, the size of sensory data has already exceeded several petabytes annually, which brings too many troubles and challenges for the data collection, which is a primary operation in IoTs and WSNs. Since the exact data collection is not affordable for many WSN and IoT systems due to the limitations on bandwidth and energy, many approximate data collection algorithms have been proposed in the last decade. This survey reviews the state of the art of approximatedatacollectionalgorithms. Weclassifythemintothreecategories: themodel-basedones, the compressive sensing based ones, and the query-driven ones. For each category of algorithms, the advantages and disadvantages are elaborated, some challenges and unsolved problems are pointed out, and the research prospects are forecasted.

RiPPAS: A Ring-Based Privacy-Preserving Aggregation Scheme in Wireless Sensor Networks.

Recently, data privacy in wireless sensor networks (WSNs) has been paid increased attention. The characteristics of WSNs determine that users' queries are mainly aggregation queries. In this paper, the problem of processing aggregation queries in WSNs with data privacy preservation is investigated. A Ring-based Privacy-Preserving Aggregation Scheme (RiPPAS) is proposed. RiPPAS adopts ring structure to perform aggregation. It uses pseudonym mechanism for anonymous communication and uses homomorphic encryption technique to add noise to the data easily to be disclosed. RiPPAS can handle both s u m ( ) queries and m i n ( ) / m a x ( ) queries, while the existing privacy-preserving aggregation methods can only deal with s u m ( ) queries. For processing s u m ( ) queries, compared with the existing methods, RiPPAS has advantages in the aspects of privacy preservation and communication efficiency, which can be proved by theoretical analysis and simulation results. For processing m i n ( ) / m a x ( ) queries, RiPPAS provides effective privacy preservation and has low communication overhead.

Avian Influenza A(H5N1) Virus in Egypt.

In Egypt, avian influenza A subtype H5N1 and H9N2 viruses are enzootic in poultry. The control plan devised by veterinary authorities in Egypt to prevent infections in poultry focused mainly on vaccination and ultimately failed. Recently, widespread H5N1 infections in poultry and a substantial increase in the number of human cases of H5N1 infection were observed. We summarize surveillance data from 2009 through 2014 and show that avian influenza viruses are established in poultry in Egypt and are continuously evolving genetically and antigenically. We also discuss the epidemiology of human infection with avian influenza in Egypt and describe how the true burden of disease is underestimated. We discuss the failures of relying on vaccinating poultry as the sole intervention tool. We conclude by highlighting the key components that need to be included in a new strategy to control avian influenza infections in poultry and humans in Egypt.

Truthful Incentive Mechanisms for Social Cost Minimization in Mobile Crowdsourcing Systems.

With the emergence of new technologies, mobile devices are capable of undertaking computational and sensing tasks. A large number of users with these mobile devices promote the formation of the Mobile Crowdsourcing Systems (MCSs). Within a MCS, each mobile device can contribute to the crowdsourcing platform and get rewards from it. In order to achieve better performance, it is important to design a mechanism that can attract enough participants with mobile devices and then allocate the tasks among participants efficiently. In this paper, we are interested in the investigation of tasks allocation and price determination in MCSs. Two truthful auction mechanisms are proposed for different working patterns. A Vickrey-Clarke-Groves (VCG)-based auction mechanism is proposed to the continuous working pattern, and a suboptimal auction mechanism is introduced for the discontinuous working pattern. Further analysis shows that the proposed mechanisms have the properties of individual rationality and computational efficiencies. Experimental results suggest that both mechanisms guarantee all the mobile users bidding with their truthful values and the optimal maximal social cost can be achieved in the VCG-based auction mechanism.

[Low-power Wireless Micro Ambulatory Electrocardiogram Node].

Ambulatory electrocardiogram (ECG) monitoring can effectively reduce the risk and death rate of patients with cardiovascular diseases (CVDs). The Body Sensor Network (BSN) based ECG monitoring is a new and efficien method to protect the CVDs patients. To meet the challenges of miniaturization, low power and high signal quality of the node, we proposed a novel 50 mmX 50 mmX 10 mm, 30 g wireless ECG node, which includes the single-chip an alog front-end AD8232, ultra-low power microprocessor MSP430F1611 and Bluetooth module HM-11. The ECG signal quality is guaranteed by the on-line digital filtering. The difference threshold algorithm results in accuracy of R-wave detection and heart rate. Experiments were carried out to test the node and the results showed that the pro posed node reached the design target, and it has great potential in application of wireless ECG monitoring.

Energy-Efficient Algorithm for Multicasting in Duty-Cycled Sensor Networks.

Multicasting is a fundamental network service for one-to-many communications in wireless sensor networks. However, when the sensor nodes work in an asynchronous duty-cycled way, the sender may need to transmit the same message several times to one group of its neighboring nodes, which complicates the minimum energy multicasting problem. Thus, in this paper, we study the problem of minimum energy multicasting with adjusted power (the MEMAP problem) in the duty-cycled sensor networks, and we prove it to be NP-hard. To solve such a problem, the concept of an auxiliary graph is proposed to integrate the scheduling problem of the transmitting power and transmitting time slot and the constructing problem of the minimum multicast tree in MEMAP, and a greedy algorithm is proposed to construct such a graph. Based on the proposed auxiliary graph, an approximate scheduling and constructing algorithm with an approximation ratio of 4 l n K is proposed, where K is the number of destination nodes. Finally, the theoretical analysis and experimental results verify the efficiency of the proposed algorithm in terms of the energy cost and transmission redundancy.