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Increasing intensity and frequency of coastal pollutions are the trajectory to be expected due to anthropogenic pressures. However, it is still unclear how and to what extent bacterioplankton communities respond to the two factors, despite the functional importance of bacterioplankton in biogeochemical cycles. In this study, significant organic pollution index (OPI) and offshore distance gradients, as respective proxies of disturbance intensity and disturbance frequency, were detected in a regional scale across the East China Sea. A multiple regression on matrices (MRM) revealed that the biogeography of bacterioplankton community depended on spatial scale, which was governed by local characters. Bacterioplankton community compositions (BCCs) were primarily governed by the conjointly direct (−0.28) and indirect (−0.48) effects of OPI, while offshore distance contributed a large indirectly effect (0.52). A SEGMENTED analysis depicted non-linear responses of BCCs to increasing disturbance intensity and disturbance frequency, as evidenced by significant tipping points. This was also true for the dominant bacterial phyla. Notably, we screened 30 OPI-discriminatory taxa that could quantitatively diagnose coastal OPI levels, with an overall 79.3% accuracy. Collectively, the buffer capacity of bacterioplankton communities to increasing disturbance intensity and disturbance frequency is limited, of which the significant tipping points afford a warning line for coastal management. In addition, coastal pollution level can be accurately diagnosed by a few OPI-discriminatory taxa.

Edge computing is an emerging technology which places computing at the edge of the network to provide an ultra-low latency. Computation offloading, a paradigm that migrates computing from mobile devices to remote servers, can now use the power of edge computing by offloading computation to cloudlets in edge-clouds. However, the task scheduling of computation offloading in edge-clouds faces a two-fold challenge. First, as cloudlets are geographically distributed, it is difficult for each cloudlet to perform load balancing without centralized control. Second, as tasks of computation offloading have a wide variety of types, to guarantee the user quality of experience (QoE) in terms of task types is challenging. In this paper, we present Petrel, a distributed and application-aware task scheduling framework for edge-clouds. Petrel implements a sample-based load balancing technology and further adopts adaptive scheduling policies according to task types. This application-aware scheduling not only provides QoE guarantee but also improves the overall scheduling performance. Trace-driven simulations show that Petrel achieves a significant improvement over existing scheduling strategies.

Aquatic animals encounter suites of novel planktonic microbes during their development. Although hosts have been shown to exert strong selection on their gut microbiota from surrounding environment, to what extent and the generality that the gut microbiota and the underlying ecological processes are affected by biotic and abiotic variations are largely unclear. Here, these concerns were explored by coupling spatiotemporal data on gut and rearing water bacterial communities with environmental variables over shrimp life stages at spatially distant locations. Shrimp gut microbiotas significantly changed mirroring their development, as evidenced by gut bacterial signatures of shrimp life stage contributing 95.5% stratification accuracy. Shrimp sourced little (2.6%-15.8%) of their gut microbiota from their rearing water. This microbial resistance was reflected by weak compositional differences between shrimp farming spatially distinct locations where species pools were distinct. Consistently, the assembly of shrimp gut microbiota was not adequately explained by the rearing water variables and bacterial community, but rather by host-age-associated biotic features. The successions of shrimp gut microbiota were droved by replacement (βsim), rather than by nestedness (βnes), while those of bacterioplankton communities were equally governed by replacement and nestedness. Our study highlights how shrimp gut bacterial community assembly is coupled to their development, rearing species pool, and that the successional pattern of host-associated communities is differed from that of free-living bacteria.

Autonomous vehicles can combine their own data with that of other vehicles to enhance their perceptive ability, and thus improve detection accuracy and driving safety. Data sharing among autonomous vehicles, however, is a challenging problem due to the sheer volume of data generated by various types of sensors on the vehicles. In this paper, we propose a low-latency, high-level (L3) data sharing protocol for connected and autonomous vehicular networks. Based on the L3 protocol, sensing results generated by individual vehicles will be broadcasted simultaneously within a limited sensing zone. The L3 protocol reduces the networking latency by taking advantage of the capture effect of the wireless transmissions occurred among vehicles. With the proposed design principles, we implement and test the L3 protocol in a simulated environment. Simulation results demonstrate that the L3 protocol is able to achieve reliable and fast data sharing among autonomous vehicles.

Soil bacterial microbial communities are important in the ecosystem function and succession of forests. Using high-throughput 16S rRNA gene sequencing and relative importance for linear regression, we explored how the structures of soil bacterial community were influenced by the environmental factors and restoration succession of secondary forests in the Miyaluo Mountains of western Sichuan, China. Using a space-for-time approach, field measurements and sampling were conducted in four stands at different stages of natural restoration. Results of distance-based multivariate analysis showed that soil pH, organic carbon, available phosphorus, and C/N ratio were the predominant environmental factors that collectively explained a 46.9% variation in the bacterial community structures. The community compositions were jointly controlled by the direct and indirect effects of the rehabilitation stages. The changes in soil environmental factors coincided with restoration succession could lead to the shifts in the relative abundance of different soil bacterial taxa. We screened 13 successional discriminant taxa that could quantitatively indicate the secondary succession subalpine stage. Collectively, our findings show that soil bacteria in different taxa are governed by different local soil variables and rehabilitation ages, which can lead to shifts in the relative abundance of different taxa in successional stages, ultimately changing the entire soil bacterial community with the succession of secondary forest.

Given the functional importance of gut microbiota in improving host fitness, increasing attention has been paid to the biogeochemical factors that govern the gut microbiota of aquatic animals. By contrast, we know little how and to what extent the gut microbiota are affected by external sources, and particularly internal sources as host ages, though this knowledge is fundamental to sustain a desirable gut microbiota. Here, we begin to assess this question by quantifying the sources of shrimp gut microbiota at the two shrimp lifestages (juvenile and adult). Dominant bacterial phyla were similar, but significantly varied in relative abundance across the shrimp gut, rearing water and sediment. However, the abundance of dominant phyla stayed relatively stable between juvenile and adult stages within a given habitat. The bacterial communities were clustered according to the habitats and stages, of which respectively constrained 22.2% and 5.9% variation in bacterial communities. SourceTracker analysis revealed that sediment facilitated much higher contributions to the source of shrimp gut microbiota than rearing water at both stages. However, when integrating the gut microbiota of juvenile as an internal source, adult gut microbiota was primarily derived from the juvenile shrimp, with a relative contribution of 66.7%. The structural equation modeling further validated this pattern. Our results uncover that a majority of commensals are derived from the younger host, a previously unrecognized source in determining gut microbiota as the shrimp ages.

The caspase family representing aspartate-specific cysteine proteases have been demonstrated to possess key roles in apoptosis and immune response. We previously demonstrated that LPS challenged Apostichopus japonicus coelomocyte could significantly induced apoptosis in vitro. However, apoptosis related molecules were scarcely investigated in this economic species. In the present work, we cloned and characterized four members caspase family from A. japonicus (designated as Ajcaspase-2, Ajcaspase-3, Ajcaspase-6, and Ajcaspase-8, respectively) by RACE. Multiple sequence alignment and structural analysis revealed that all Ajcaspases contained the conservative CASC domain at C terminal, in which some unique features for each Ajcaspase made them different from each other. These specific domains together with phylogenetic analysis supported that all these four identified proteins belonged to novel members of apoptotic signaling pathway in sea cucumber. Tissue distribution analysis revealed that four Ajcaspase genes were constitutively expressed in all examined tissues. The expression of Ajcaspase-2 was tightly correlated with that of Ajcaspase-8 in each detected tissues. Ajcaspase-3 and Ajcaspase-6 transcripts were both highly expressed in immune tissue of coelomocytes. Furthermore, the Vibrio splendidus challenged sea cucumber coelomocytes could significantly up-regulate the mRNA expressions of four genes. The expression levels of Ajcaspase-2 and Ajcaspase-8 were relative earlier than those of Ajcaspase-6 and Ajcaspase-3, respectively, which could be inferred that Ajcapase-2 might directly modulate Ajcaspase-6, and Ajcaspase-8 initiate the expression of Ajcaspase-3. The induce expressions differed among each Ajcaspase depending upon their roles such as initiator or effector caspase. All our results demonstrated that four Ajcaspases present diversified functions in apoptotic cascade signaling pathway of sea cucumber under immune response.

Due to the use of the cloud computing technology, the ownership is separated from the administration of the data in cloud and the shared data might be migrated between different clouds, which would bring new challenges to data secure creation, especially for the data privacy protection. We propose a User-centric data secure creation scheme (UCDSC) for the security requirements of resource owners in cloud. In this scheme, a data owner first divides the users into different domains. The data owner encrypts data and defines different secure managing policies for the data according to domains. To encrypt the data in UCDSC, we present an algorithm based on Access control conditions proxy re-encryption (ACC-PRE), which is proved to be master secret secure and Chosen-ciphertext attack (CCA) secure in random oracle model. We give the application protocols and make the comparisons between some existing approaches and UCDSC.

High-density aquaculture has led to increasing occurrences of diseases in shrimp. Thus, it is imperative to establish effective and quantitative strategies for preventing and predicting these diseases. Water quality indices and investigations of specific pathogen abundance provide only a qualitative evaluation of the risk of shrimp disease and can be inaccurate. To address these shortcomings, we introduced intestinal indicative assemblages as independent variables with which to quantitatively predict incidences of shrimp disease. Given the ignorance regarding the niches differences in the shrimp intestine throughout its developmental stages, the use of probiotics in aquaculture has had limited success. Therefore, we propose the exploration of effective probiotic bacteria from shrimp intestinal flora and the establishment of therapeutic strategies dependent on shrimp age. Following ecological selection principles, we hypothesize that the larval stage provides the best opportunity to establish a desired gut microbiota through preemptive colonization of the treated rearing water with known probiotics. To employ this strategy, however, substantial barriers must be overcome.

A multi-authority attribute-based access control system for cloud storage is proposed.An adaptively secure multi-authority CP-ABE (MA-CP-ABE) scheme in the standard model.A decryption outsourcing method for the proposed MA-CP-ABE scheme.An attribute-level revocation approach achieves back secrecy and forward secrecy. Multi-Authority Attribute-Based Encryption (MA-ABE) is an emerging cryptographic primitive for enforcing fine-grained attribute-based access control on the outsourced data in cloud storage. However, most of the previous multi-authority attribute-based systems are either proven to be secure in a weak model or lack of efficiency in user revocation. In this paper, we propose MAACS (Multi-Authority Access Control System), a novel multi-authority attribute-based data access control system for cloud storage. We construct a new multi-authority ciphertext-policy ABE (MA-CP-ABE) scheme with decryption outsourcing. The decryption overhead for users is largely eliminated by outsourcing the undesirable bilinear pairing operations to the cloud servers. The proposed MA-CP-ABE scheme is proven adaptively secure in the standard model and supports any monotone access policy. We also design an efficient attribute-level user revocation approach with less computation cost. The security analysis, numerical comparisons and implementation results indicate that our MAACS is secure, efficient and scalable.

Because NAND flash memory exhibits excellent performances in terms of shock resistance, non-volatility, fast access speed, small size, and lower power consumption, it has become the dominant storage medium of consumer electronics such as smart phones and portable media players. However, these consumer electronics suffer from limited main memory. Therefore, an efficient page replacement algorithm should be proposed for consumer electronics to reclaim obsolete pages and obtain free page frames for requested pages. In this paper, a history-aware page replacement algorithm is proposed for NAND flash-based consumer electronics. The proposed page replacement algorithm adapts itself to the runtime workloads and gives each dirty page a second chance to stay in the main memory. Experimental results show that the proposed page replacement algorithm performs better than the state-of-the-art page replacement algorithms in terms of the page hit ratio, the number of write operations, and the energy consumption.

There is evidence that gut microbial signatures are indicative of host health status. However, few efforts have been devoted to establishing an applicable technique for determining disease incidence by using gut microbial signatures. Herein, we established a quantitative PCR (qPCR)-based approach to detect the relative abundances of gut disease-discriminatory phyla, which in turn afforded independent variables for quantitatively determining the incidence of shrimp disease. Given the temporal dynamics of gut bacterial communities as healthy shrimp aged, we identified disease-discriminatory phyla after ruling out age-discriminatory phyla. The top 10 disease-discriminatory phyla contributed to an overall 93.2% accuracy in diagnosis (n = 103 samples from shrimp that were determined with high confidence to be healthy or that exhibited apparent disease symptoms and subsequent death), with 70% diagnosis accuracy at the disease onset stage, when symptoms or signs of disease were not apparent. 16S rRNA gene-targeted group-specific primers of five disease-discriminatory phyla were then designed according to their compositions within shrimp gut microbiota, and other primers were borrowed from previous studies. The relative abundances of the 10 disease-discriminatory phyla assayed by qPCR exhibited a high consistency (r = 0.946, P < 0.001) with those detected by Illumina sequencing. Notably, using the profiles of disease-discriminatory phyla assayed by qPCR and the corresponding weight coefficients as independent variables, we were able to accurately estimate the incidences of future disease outcome. This work establishes an applicable technique to quantitatively determine the incidence and onset of shrimp disease, which is a valuable attempt to translate scientific research into a practical application. IMPORTANCE Current studies have identified gut microbial signatures of host health using high-throughput sequencing (HTS) techniques. However, HTS is still expensive and time-consuming and requires a high technical ability, thereby impeding its application in routine monitoring in aquaculture. Hence, it is necessary to seek an alternative strategy to overcome these shortcomings. Herein, we establish a qPCR-based approach to detect the relative abundances of gut disease-discriminatory phyla, which in turn afford independent variables to quantitatively determine the incidence and onset of shrimp disease. Notably, there is a high consistency between the accuracies of disease diagnosis achieved by qPCR and HTS. This applicable technique makes important progress toward defining a diseased state in shrimp and toward solving an important animal health management-driven economic problem.

Microorganisms contribute diverse and fundamental roles in biogeochemical processes. In a given microbial community, individuals interact with one another to form complex regulatory networks in which gatekeepers contribute disproportional roles in sustaining stability, dynamics, and function. Owing to the ecological and functional importance of microbial gatekeeper, this review provides an overview on its history, identification, roles, application in biological sciences, and clinical diagnostics. The roles of microbial gatekeepers can be beneficial or detrimental, which depends on our purpose. As the field is rather new, some limitations are raised, and further efforts devoted to solving these concerns are proposed. Collectively, gatekeepers provide promising targets for sustaining and re-establishing a desired microbial community. However, substantial obstacles, such as factors governing gatekeepers, must be overcome to manipulate gatekeepers as positive guys.

Climate change-induced glacial melting is a global phenomenon. The effects of climate change-induced melting on the microbial ecology in different glacial-fed aquatic systems have been well illuminated, but the resolution of seasonal dynamics was still limited. Here, we studied bacterial community composition and diversity in a glacial-fed Tibetan lake, Lake Ranwu, to elucidate how glacial-fed aquatic ecosystems respond to the seasonal glacial melting. Obvious seasonal variations of bacterial dominant groups were found in Lake Ranwu and inlet rivers. In April, the majority of OTUs belonged to the Bacteroidetes, Actinobacteria and Proteobacteria. The Proteobacteria increased to the most abundant phylum in July and November, while the Bacteroidetes and Actinobacteria decreased about 50% over seasons. Most key discriminant taxa of each season's community strongly associated with specific environmental variables, suggesting their adaptation to seasonal environments. Bacterial alpha diversity varied among seasons and exhibited strongly negative correlations with conductivity. Conductivity was the major driving force in determining the seasonal variation of bacterial community composition. Fluctuated conductivity was one of the consequences of seasonal melting of glaciers. This study offered evidence for the unique seasonal dynamics pattern of bacterial communities responding to glacial melting. Moreover, this study may provide a reference for assessing the long-term effects of glacial retreat on glacial-fed aquatic ecosystems.

With the widespread adoption of mobile devices, an increasingly number of personal data are stored in mobile devices that using flash memory as storage medium. Personal data privacy may also be leaked because of unauthorized access or resale of mobile devices. How to effectively protect users' data privacy and securely delete invalid data, which brings a great challenge to the data secure deletion in flash memory. In order to tackle these problems, we propose a novel data secure deletion scheme based on key derivation encryption algorithm for mobile devices. Firstly, we construct a node key tree based on flash hierarchical structure, and propose a key derivation encryption algorithm to generate data key to encrypt user data. Furthermore, we combine partial block erasure with partial key deletion method to delete both the ciphertext data and the partial key component after expired. The security analysis shows that the proposed scheme is able to implement data privacy protect and secure deletion of invalid data. Performance analysis and experimental results indicate that the proposed scheme is effective and efficient.

Increasing evidence indicates that dysbiosis in the gut microbiota contributes to disease pathogenesis. However, whether certain taxa are universally indicative of diverse shrimp diseases is unclear thus far. We conducted a meta-analysis to explore the divergences in gut microbiota between healthy and diseased shrimp. The gut bacterial communities of healthy shrimp varied significantly (P < 0.05 in each comparison) over ontogenetic stages, and were distinct from the corresponding diseased cohorts at each life stage. Both phylogenetic-based mean nearest taxon distance analysis and multivariate dispersion testing revealed that shrimp disease weakened the relative importance of deterministic processes in governing the gut microbiota. Partitioning beta diversity analysis indicated that temporal turnover governed the gut microbiota as healthy shrimp aged, whereas this trend was retarded in disease cohorts, concurrent with an increased nestedness. After ruling out the age-discriminatory and disease-specific orders, a high diagnosed accuracy (85.9%) of shrimp health status was achieved by using the profiles of the 11 universal disease-discriminatory orders as independent variables. These findings improve current understanding of how disease alters the ecological processes that govern the shrimp gut microbiota assembly, and exemplifies the potential application of universal bacterial signatures to diagnose the incidence of diverse shrimp diseases, irrespective of causal pathogens.

Aquatic animals are frequently suffered from starvation due to restricted food availability or deprivation. It is currently known that gut microbiota assists host in nutrient acquisition. Thus, exploring the gut microbiota responses would improve our understanding on physiological adaptation to starvation. To achieve this, we investigated how the gut microbiota and shrimp digestion and immune activities were affected under starvation stress. The results showed that the measured digestion activities in starved shrimp were significantly lower than in normal cohorts; while the measured immune activities exhibited an opposite trend. A structural equation modeling (SEM) revealed that changes in the gut bacterial community were directly related to digestive and immune enzyme activities, which in turn markedly affected shrimp growth traits. Notably, several gut bacterial indicators that characterized the shrimp nutrient status were identified, with more abundant opportunistic pathogens in starved shrimp, although there were no statistical differences in the overall diversity and the structures of gut bacterial communities between starved and normal shrimp. Starved shrimp exhibited less connected and cooperative interspecies interaction as compared with normal cohorts. Additionally, the functional pathways involved in carbohydrate and protein digestion, glycan biosynthesis, lipid and enzyme metabolism remarkably decreased in starved shrimp. These attenuations could increase the susceptibility of starved shrimp to pathogens infection. In summary, this study provides novel insights into the interplay among shrimp digestion, immune activities and gut microbiota in response to starvation stress.

One common notion is emerging that gut eukaryotes are commensal or beneficial, rather than detrimental. To date, however, surprisingly few studies have been taken to discern the factors that govern the assembly of gut eukaryotes, despite growing interest in the dysbiosis of gut microbiota-disease relationship. Herein, we firstly explored how the gut eukaryotic microbiotas were assembled over shrimp postlarval to adult stages and a disease progression. The gut eukaryotic communities changed markedly as healthy shrimp aged, and converged toward an adult-microbiota configuration. However, the adult-like stability was distorted by disease exacerbation. A null model untangled that the deterministic processes that governed the gut eukaryotic assembly tended to be more important over healthy shrimp development, whereas this trend was inverted as the disease progressed. After ruling out the baseline of gut eukaryotes over shrimp ages, we identified disease-discriminatory taxa (species level afforded the highest accuracy of prediction) that characteristic of shrimp health status. The profiles of these taxa contributed an overall 92.4% accuracy in predicting shrimp health status. Notably, this model can accurately diagnose the onset of shrimp disease. Interspecies interaction analysis depicted how the disease-discriminatory taxa interacted with one another in sustaining shrimp health. Taken together, our findings offer novel insights into the underlying ecological processes that govern the assembly of gut eukaryotes over shrimp postlarval to adult stages and a disease progression. Intriguingly, the established model can quantitatively and accurately predict the incidences of shrimp disease.

Contrasting temperature Bacterial community Turnover rate Temperature relationship Indicator species A B S T R A C T Soil microbial communities potentially mediate the feedbacks to climate change, and thus, the understanding of microbial ecology is central to predict future global warming. However, the direct warming effects on microbial communities are uncertain due to the confounding effects of plant traits and soil heterogeneities. Here, we exposed alpine meadow soil microcosms to temperature between 10 and 40 � C for 28 days, to evaluate the temperature relationship of the bacterial community structure and microbial functions. Our results showed that sustained exposure to contrasting temperature produced compositionally and functionally distinct microbial communities. The degree of these changes was dependent on the magnitude of warming, as shown by a consistent increase in the dissimilarities and a shift of the carbon (C) use pattern along the temperature gradient. We found that the bacterial community temporal dynamics followed a gradual process of succession, and the turnover rate was substantially accelerated (P = 0.012) by warmer temperatures; every 1 � C elevation in soil temperature was estimated to increase the turnover by 0.001. Consistently, contrasting temperature was found to be the dominant factor explained 6.1% of the total variation of the microbial community structures; however, the incubation duration and the interaction between incubation temperature and duration explained 5.4% and 4.1% of the variation, respectively. As anticipated, the shift in bacterial community rapidly translated to a similar change in enzymes activities and C utilization. In addition, potential indicator species were screened; these species characterized the temperature gradient. Collectively, our findings indicate that direct warming effects on soil bacterial community could substantially alter certain function and that contrasting temperatures would accelerate the bacterial community turnover– temperature relationship in this alpine meadow soil.

Multi-authority attribute-based encryption ABE is a generation of ABE where the descriptive attributes are managed by different authorities. In current multi-authority ABE schemes, the scale of attribute universe employed in encryption is restricted by various predefined thresholds. In this paper, we propose an unbounded multi-authority ciphertext-policy ABE system without such restriction. Our scheme consists of multiple attribute authorities AAs, one central authority CA, and users labeled by the set of attributes. Each AA governs a different universe of attributes and operates separately. Moreover, there is no cooperation between the CA and AAs. To provide the private keys for a user, the AAs first issue partial attribute-related keys according to the attributes; the CA then issues identity-related keys and links these attribute-keys with the user's global identifier. Both the identity-related and the linked attribute-related keys will be used in decryption. The proposed multi-authority ciphertext-policy ABE scheme can support arbitrary linear secret sharing scheme as the access policy. Performance analysis and security proof indicate that our scheme is efficient and secure. Copyright © 2015 John Wiley & Sons, Ltd.

Understanding biological diversity and distribution patterns at multiple spatial scales is a central issue in ecology. Here, we investigated the biogeographical patterns of microbial functional genes in 24 heath soils from across the Arctic using GeoChip-based metagenomics and principal coordinates of neighbour matrices (PCNM)-based analysis. Functional gene richness varied considerably among sites, while the proportions of each major functional gene category were evenly distributed. Functional gene composition varied significantly at most medium to large spatial scales, and the PCNM analyses indicated that 14–20% of the variation in total and major functional gene categories could be attributed primarily to relatively large-scale spatial effects that were consistent with broad-scale variation in soil pH and total nitrogen. The combination of variance partitioning and multi-scales analysis indicated that spatial distance effects accounted for 12% of the total variation in functional gene composition, whereas environmental factors accounted for only 3%. This small but significant influence of spatial variation in determining functional gene distributions contrasts sharply with typical microbial phylotype/species-based biogeographical patterns (including these same Arctic soil samples), which are primarily determined by contemporary environmental heterogeneities. Therefore, our results suggest that historical contingencies such as disturbance events, physical heterogeneities, community interactions or dispersal barriers that occurred in the past, have some significant influence on soil functional gene distribution patterns.

The underlying mechanisms of microbial community assembly in connective coastal environments are unclear. The coastal water area of northern Zhejiang, East China Sea, is a complex marine ecosystem with multiple environmental gradients, where the distributions and determinants of bacterioplankton communities remain unclear. We collected surface water samples from 95 sites across eight zones in this area for investigating bacterial community with 16S rRNA gene high-throughput sequencing. Bacterial alpha-diversity exhibits strong associations with water chemical parameters and latitude, with 75.5% of variation explained by suspended particle. The composition of dominant phyla can group the sampling sites into four bacterial provinces, and most key discriminant phyla and families/genera of each province strongly associate with specific environmental features, suggesting that local environmental conditions shape the biogeographic provincialism of bacterial taxa. At a broader and finer phylogenetic scale, bacterial beta-diversity is dominantly explained by the shared variation of environmental and spatial factors (63.3%); meanwhile, the environmental determinants of bacterial β-diversity generally exhibit spatially structured patterns, suggesting that bacterial assembly in surface water is highly controlled by spatially structured environmental gradients in this area. This study provides evidence for the unique biogeographic pattern of bacterioplankton communities at an entire scale of this marine ecosystem.

With rapidly development of wireless communication, more mobile devices are used in our daily life. Although the need for accessing a wireless network is evident, new problems, such as keeping and preserving user identity’s privacy, should be greatly concerned. Attribute based signature scheme is an important cryptographic primitive which provides a powerful way for user to control their privacy. In wireless environment, the capacity of wireless channel is also valuable resources which is limited. More information can be transmitted through the wireless channel when the cost of using signature to verify the message becomes less. In order to reduce the bandwidth needed to transmit attribute based signatures and keep signer’s privacy, attribute based multisignature scheme (ABMS) was proposed in this paper. Moreover, we formalize and construct the ABMS. Our scheme is existentially unforgeable against chosen message attack on Computational Diffie-Hellman (CDH) assumption in the standard model. The simulation shows that our ABMS scheme is more appropriate for wireless communication to guarantee integrity of the data.

It is now recognized that some gut diseases attribute to polymicrobial pathogens infections. Thus, traditional isolation of single pathogen from disease subjects could bias the identification of causal agents. To fill this gap, using Illumina sequencing of the bacterial 16S rRNA gene, we explored the dynamics of gut bacterial communities over a shrimp disease progression. The results showed significant differences in the gut bacterial communities between healthy and diseased shrimp. Potential pathogens were inferred by a local pathogens database, of which two OTUs (affiliated with Vibrio tubiashii and Vibrio harveyi) exhibited significantly higher abundances in diseased shrimp as compared to healthy subjects. The two OTUs cumulatively contributed 64.5% dissimilarity in the gut microbiotas between shrimp health status. Notably, the random Forest model depicted that profiles of the two OTUs contributed 78.5% predicted accuracy of shrimp health status. Removal of the two OTUs from co-occurrence networks led to network fragmentation, suggesting their gatekeeper features. For these evidences, the two OTUs were inferred as candidate pathogens. Three virulence genes (bca, tlpA, and fdeC) that were coded by the two candidate pathogens were inferred by a virulence factor database, which were enriched significantly (P

Summary Collaborative cloud applications have become the dominant application mode in the big data era. These applications usually generate plenty of cooperative files, which share their ownerships with all collaborative participants. Data deduplication is a promising solution to improve the storage efficiency and save the user expenditure. However, it remains an open issue on how to securely prove the shared ownerships for the shared files and address the attacks on account of using data deduplication. To tackle the above issue, in this paper, we introduce a novel concept of the Proof of Shared oWnership (PoSW) and construct a secure multi-server-aided PoSW (ms-PoSW) scheme for securing client-side deduplication for the shared files, which is based on the convergent encryption, secret sharing, and bloom filter. In the ms-PoSW scheme, we employ a sharing convergent key to avoid the single point of failure, introduce the secret sharing algorithm to implement the shared ownership, and construct a novel interaction protocol between the shared owners and the cloud server to prove the shared ownership. Furthermore, a hybrid PoSW scheme is constructed to address the secure proof of hybrid cloud architectures. Finally, security analysis and performance evaluation show the security and efficiency of the proposed schemes.

As a new method of the Internet of Things (IoT), the mobile crowdsensing provides a novel way to realize the ubiquitous social perception. From the point of the game theory, this paper addresses the reputation incentive mechanism and discusses the prisoner's dilemma in the mobile crowdsensing. Firstly, we give a formal definition of the sensing user's contribution based on the accuracy in data analysis, and propose a reputation incentive mechanism based on this contribution, which considers the privacy protection of the sensing data and encourages more sensing users to continually provide the highquality data to participate in the mobile crowdsensing. Furthermore, we observe that the sensing user's benefits not only depend on their own contribution, but also rely on the outcome of the final data transaction between the service provider and the mediator. However, this data transaction is vulnerable to the prisoner's dilemma due to the selfish choice of the both parties. Therefore, we analyze and discuss the prisoner's dilemma in the above data transactionsand give the corresponding solutions. Finally, we point outsome future research directions about privacy protection ofthe mobile crowdsensing.

High mobility group box protein 3 (HMGB3) regulates proliferation and inflammatory response in vertebrates. However, its functional roles in invertebrates are largely unknown. In this study, a HMGB3 homologue molecule was identified from Apostichopus japonicus (designated as AjHMGB3) by RACE approach. The full-length cDNA of AjHMGB3 was of 2298 bp with an open reading frame of 1320 bp encoding a 439-amino-acid (aa) residue protein. Structural analysis then conducted and the results revealed that AjHMGB3 processed two conserved HMGBs (133–204 and 210–279 aa) and an acidic tail. The results of subsequent multiple sequence alignment and phylogenetic analysis both indicated that AjHMGB3 belongs to a new member of HMGB3 protein subfamily. Furthermore, AjHMGB3 was expressed in all examined tissues except in tentacles and particularly highly expressed in the intestine, as indicated by spatial expression analysis results. The Vibrio splendidus challenge in vivo and lipolysaccharide (LPS) stimulation in vitro can significantly upregulate the mRNA expression of AjHMGB3 in coelomocytes. This finding is consistent with the expression profiles of TLR cascade members. We further investigated the expression profiles of AjMyD88 and Ajp105 after the gain- or loss-of-function of AjHMGB3 in coelomocytes. The results showed that AjMyD88 and Ajp105 were upregulated 2.19- and 2.83-fold in AjHMGB3 overexpressed treatment and downregulated 0.38- and 0.43-fold in the AjHMGB3 silencing group. The p50 subunit displayed expression profiles that are identical to those of AjMyD88 and Ajp105 according to the Western blot results. In the same condition, the respiratory burst was increased by 37.5% in the AjHMGB3 overexpressed group and depressed by 28.2% in the AjHMGB3 knock-down group. Our present findings collectively suggested that AjHMGB3 acted as an NF-κB activator and produced ROS production in sea cucumbers.

It is widely accepted that bacterial community composition and diversity in remote alpine lakes are structured by environmental conditions such as nutrient status and temperature. However, the mechanisms that underlie and structure bacterial community composition and diversity in alpine lakes remain unclear. We used 16S rRNA gene-based Illumina MiSeq sequencing to investigate the complex ecological interactions between bacterial communities and nutrient status in Kalakuli Lake, an alpine glacial-fed lake in Muztagh Ata of the westernmost Tibetan Plateau. Our results indicated that the bacterial community was dominated by the Actinobacteria and Proteobacteria. The results of threshold estimates showed that there were apparent shifts in dominance from the Proteobacteria to Actinobacteria groups associated with increasing carbon to nitrogen (C:N) ratio, and the change points were 6.794 and 2.448, respectively. Using multiple statistical methods, we found that the abiotic factors of dissolved organic carbon and total nitrogen had substantial impacts on bacterial diversity, while bacterial community compositions were significantly correlated with both the biotic element of bacterial abundance and the abiotic ones, temperature and pH. These findings demonstrated that the C:N ratio played a significant role in shifting dominant bacterial assemblages in the Kalakuli watershed and provided evidence of nutrients affecting bacterial community composition and diversity. We argue that this study could further shed light on how climate change-induced glacial retreat may impact bacterial communities in glacial-fed lakes under future global warming scenarios.

K-means algorithm is an important type of clustering algorithm and the foundation of some data mining methods. But it has the risk of privacy disclosure in the process of clustering. In order to solve this problem, Blum et al. proposed a differential privacy K-means algorithm, which can prevent privacy disclosure effectively. However, the availability of clustering results is reduced due to the added noise. In this paper, we propose a novel DPLK-means algorithm based on differential privacy, which improves the selection of the initial center points through performing the differential privacy K-means algorithm to each subset divided by the original dataset. Performance evaluation shows that our algorithm improves the availability of clustering results compared to the existing differential privacy K-means algorithm at the same privacy level.

The explosive growth of multimedia data promotes us to enter the era of big data. To improve the storage efficiency and reduce the management expenditure of these massive data, deduplication is a promising technology to meet these requirements. However, it arises serious privacy concerns and poses new security challenges, such as privacy leakage and unauthorized access. To tackle these problems, in this paper, we propose a novel role symmetric encryption (RSE) algorithm and construct an authorized deduplication scheme (RSEDup) based on the role symmetric encryption to achieve the authorized deduplication in cloud. The RSEDup scheme is the first solution to prevent privacy leakage and achieve the authorized deduplication effectively. Performance evaluation shows the efficiency of the proposed scheme.

Collaborative cloud applications are increasingly popular in our daily life, and generate plenty of cooperative files. The ownerships of these files are jointly shared by all participants. However, it is still a challenge to keep secure access and storage to those shared files, while ensuring the cloud storage efficiency. To tackle this problem, in this paper, we formalize a novel notion called Proof of Shared oWnership (PoSW), and propose a specific PoSW scheme to implement both secure ownership verification and data deduplication. In the PoSW scheme, we employ the convergent encryption algorithm to protect the content confidentiality of the shared file, introduce the secret file dispersal and secret sharing algorithm to implement the shared authorization and file ownership, and construct a novel interaction protocol between the file owners and the cloud server to verify the shared ownership and achieve deduplication to the shared file. Security analysis and performance evaluation show the security and efficiency of the proposed scheme.

Support vector machine (SVM) as a learning machine has shown a good learning ability and generalization ability in classification, regression and forecasting. Because of its excellent learning performance, SVM has always been a hotspot in machine learning. In hence, this paper will make a more systematic introduction of SVM, including the theory of SVM, the summarization and comparison of the quadratic programming optimizations and parameter optimizations for SVM and the introduction of some new SVMs, like FSVM, TSVM, MSVM, etc. Then, the applications of SVM in real life will be presented, especially, in the area of mobile multimedia. Finally, we conclude with a discussion of the direction of further SVM improvement.

With the rapid development of versatile cloud services, it becomes increasingly susceptible to use cloud services to share data in a friend circle in the cloud computing environment. Since it is not feasible to implement full lifecycle privacy security, access control becomes a challenging task, especially when we share sensitive data on cloud servers. In order to tackle this problem, we propose a key-policy attribute-based encryption with time-specified attributes (KP-TSABE), a novel secure data self-destructing scheme in cloud computing. In the KP-TSABE scheme, every ciphertext is labeled with a time interval while private key is associated with a time instant. The ciphertext can only be decrypted if both the time instant is in the allowed time interval and the attributes associated with the ciphertext satisfy the key’s access structure. The KP-TSABE is able to solve some important security problems by supporting user-defined authorization period and by providing fine-grained access control during the period. The sensitive data will be securely self-destructed after a user-specified expiration time. The KP-TSABE scheme is proved to be secure under the decision $l$ -bilinear Diffie-Hellman inversion ( $l$ -Expanded BDHI) assumption. Comprehensive comparisons of the security properties indicate that the KP-TSABE scheme proposed by us satisfies the security requirements and is superior to other existing schemes.

Attribute-based encryption (ABE) has been considered as a promising cryptographic primitive for realising information security and flexible access control. However, the characteristic of attributes is treated as the identical level in most proposed schemes. Lattice-based cryptography has been attracted much attention because of that it can resist to quantum cryptanalysis. In this study, lattice-based threshold hierarchical ABE (lattice-based t -HABE) scheme without random oracles is constructed and proved to be secure against selective attribute set and chosen plaintext attacks under the standard hardness assumption of the learning with errors problem. The notion of the HABE scheme can be considered as the generalisation of traditional ABE scheme where all attributes have the same level.

With the rapid development of versatile cloud services, it becomes increasingly susceptible to expose users’ sensitive data into the cloud computing environment. In this paper, we propose a full lifecycle privacy protection scheme for sensitive data (FullPP), which is based on identity-based timed-release encryption (ID-TRE) algorithm and distributed hash table (DHT) network. In the FullPP scheme, we first encrypt the sensitive data into a ciphertext, which is broken up into extracted ciphertext and encapsulated ciphertext by using an extracting algorithm. Then, we leverage the ID-TRE algorithm to encrypt the decryption key and combine the key’s ciphertext with the extracted ciphertext to generate ciphertext shares. Finally, we distribute the ciphertext shares into the DHT network and store the encapsulated ciphertext into cloud servers. To recover the plaintext of the sensitive data, sufficient ciphertext shares, ID-TRE private key and the encapsulated ciphertext should be obtained during the lifecycle of the sensitive data. As a result, FullPP is able to provide full lifecycle privacy protection for users’ sensitive data by making it unreadable before a predefined time and automatically destructed after expiration. Security analysis indicates that the FullPP scheme is able to resist against both traditional attacks on the cloud servers and Sybil attacks on the DHT network. Experiment result shows that the FullPP scheme proposed by us is more effective and efficient than other existing schemes.

Existing works for securing network coding against wiretapping either incur high coding complexity or bring large bandwidth overhead. For exploiting the lightweight security mechanism for resource-constrained networks, an efficient secure coding scheme is proposed in conjunction with the inherent mixing characteristic of network coding. The key idea is to minimize the randomizing operations to the entire plaintext data. The proposed scheme is shown to have properties of lightweight security complexity and lower communication overhead compared with the existing traditional solutions, and can be easy in implementation and combination with classical cryptography techniques.

In multi-authority attribute-based encryption ABE systems, each authority manages a different attribute universe and issues the private keys to users. However, the previous multi-authority ABE schemes are subject to such restrictions during initializing the systems: either the attribute universe is polynomially sized and the attributes have to be enumerated or the attribute universe can be exponentially large, but the size of the set of attributes, which will be used in encryption, is not more than a predefined fixed value. These restrictions prevent multi-authority ABE schemes from being deployed in dynamic practice applications. In this paper, we present a large universe decentralized key-policy ABE scheme without such additional limitation. In our scheme, there is no requirement of any central authority. Each attribute authority executes independently from the others and can join or depart the system allodiality. Our system supports any monotone access policy. The proposed scheme is constructed on prime order groups and proved selectively secure in the standard model. To the best of our knowledge, our scheme is the first large universe decentralized key-policy ABE system in the standard model. Copyright © 2014 John Wiley & Sons, Ltd.

Patterns of microbial distribution represent the integrated effects of historical and biological processes and are thus a central issue in ecology. However, there is still active debate on whether dispersal limitation contributes to microbial diversification in strongly connected systems. In this study, sediment samples were collected along a transect representing a variety of seawater pollution levels in the East China Sea. We investigated whether changes in sediment bacterial community structures would indicate the effects of the pollution gradient and of dispersal limitation. Our results showed consistent shifts in bacterial communities in response to pollution. More geographically distant sites had more dissimilar communities ( r = −0.886, P < 0.001) in this strongly connected sediment ecosystem. A variance analysis based on partitioning by principal coordinates of neighbor matrices (PCNM) showed that spatial distance (dispersal limitation) contributed more to bacterial community variation (8.2%) than any other factor, although the environmental factors explained more variance when combined (11.2%). In addition, potential indicator taxa (primarily affiliated with Deltaproteobacteria and Gammaproteobacteria ) were identified; these taxa characterized the pollution gradient. This study provides direct evidence that dispersal limitation exists in a strongly connected marine sediment ecosystem and that candidate indicator taxa can be applied to evaluate coastal pollution levels.

The close correlation between the incidence of shrimp disease and the surrounding microbial community is well established. However, it remains uncertain whether particular bacterial assemblages are indicative of shrimp health status (healthy or diseased). To test this hypothesis, we used 454 pyrosequencing to compare the bacterioplankton composition of ponds with healthy shrimp populations (PHS) with that of ponds with diseased shrimp populations (PDS). The results showed that the bacterial communities in PDS were markedly distinct (P

Soil fungi fill pivotal ecological roles in biogeochemical processes, particularly dominating decomposition of lignin. Little is known, however, about the responses of different fungal groups to climate warming with respect to bacteria. In this study, using barcode pyrosequencing, we showed that short-term (15 months) of field exposure of an alpine meadow to warming (elevated 1 and 2 °C) did not markedly alter the overall soil fungal community structures and α-diversity on Tibetan Plateau, but the average β-diversity dramatically decreased in response to warming. However, soil respiration rates were stimulated in the growing season, which significantly (P

Each cloud service has numerous owners and tenants, so it is necessary to construct a privacy preserving identity management and access control mechanism for cloud computing. On one hand, cloud service providers (CSP) depend on tenant’s identity information to enforce appropriate access control so that cloud resources are only accessed by the authorized tenants who are willing to pay. On the other hand, tenants wish to protect their personalized service access patterns, identity privacy information and accessing newfangled cloud services by on-demand ways within the scope of their permissions. There are many identity authentication and access control schemes to address these challenges to some degree, however, there are still some limitations. In this paper, we propose a new comprehensive approach, called Privacy pReserving Identity and Access Management scheme, referred to as PRIAM, which is able to satisfy all the desirable security requirements in cloud computing. The main contributions of the proposed PRIAM scheme are threefold. First, it leverages blind signature and hash chain to protect tenant’s identity privacy and implement secure mutual authentication. Second, it employs the service-level agreements to provide flexible and on-demand access control for both tenants and cloud services. Third, it makes use of the BAN logic to formally verify the correctness of the proposed protocols. As a result, our proposed PRIAM scheme is suitable to cloud computing thanks to its simplicity, correctness, low overhead, and efficiency.

In cloud computing environment, especially in big data era, adversary may use data deduplication service supported by the cloud service provider as a side channel to eavesdrop users' privacy or sensitive information. In order to tackle this serious issue, in this paper, we propose a secure data deduplication scheme based on differential privacy. The highlights of the proposed scheme lie in constructing a hybrid cloud framework, using convergent encryption algorithm to encrypt original files, and introducing differential privacy mechanism to resist against the side channel attack. Performance evaluation shows that our scheme is able to effectively save network bandwidth and disk storage space during the processes of data deduplication. Meanwhile, security analysis indicates that our scheme can resist against the side channel attack and related files attack, and prevent the disclosure of privacy information.

The concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have been rising due to human activities. However, little is known about how such increases influence soil microbial communities. We hypothesized that elevated CO2 (eCO2) and elevated O3 (eO3) would significantly affect the functional composition, structure and metabolic potential of soil microbial communities, and that various functional groups would respond to such atmospheric changes differentially. To test these hypotheses, we analyzed 96 soil samples from a soybean free-air CO2 enrichment (SoyFACE) experimental site using a comprehensive functional gene microarray (GeoChip 3.0). The results showed the overall functional composition and structure of soil microbial communities shifted under eCO2, eO3 or eCO2+eO3. Key functional genes involved in carbon fixation and degradation, nitrogen fixation, denitrification and methane metabolism were stimulated under eCO2, whereas those involved in N fixation, denitrification and N mineralization were suppressed under eO3, resulting in the fact that the abundance of some eO3-supressed genes was promoted to ambient, or eCO2-induced levels by the interaction of eCO2+eO3. Such effects appeared distinct for each treatment and significantly correlated with soil properties and soybean yield. Overall, our analysis suggests possible mechanisms of microbial responses to global atmospheric change factors through the stimulation of C and N cycling by eCO2, the inhibition of N functional processes by eO3 and the interaction by eCO2 and eO3. This study provides new insights into our understanding of microbial functional processes in response to global atmospheric change in soybean agro-ecosystems.

The elevational patterns of diversity for plants and animals have been well established over the past century. However, it is unclear whether there is a general elevational distribution pattern for microbes. Changbai Mountain is one of few well conserved natural ecosystems, where the vertical distribution of vegetation is known to mirror the vegetation horizontal zonation from temperate to frigid zones on the Eurasian continent. Here, we present a comprehensive analysis of soil bacterial community composition and diversity along six elevations representing six typical vegetation types from forest to alpine tundra using a bar-coded pyrosequencing technique. The bacterial communities differed dramatically along elevations (vegetation types), and the community composition was significantly correlated with soil pH, carbon/nitrogen ratio (C/N), moisture or total organic carbon (TOC), respectively. Phylogenetic diversity was positively correlated with soil pH ( P = 0.024), while phylotype richness was positively correlated with soil pH ( P = 0.004), total nitrogen (TN) ( P = 0.030), and negatively correlated with C/N ratio ( P = 0.021). Our results emphasize that pH is a better predictor of soil bacterial elevational distribution and also suggest that vegetation types may indirectly affect soil bacterial elevational distribution through altering soil C and N status.

Our previously described environmental DNA extraction method has been widely used in environmental microbial community analysis. However, residual humic substances may remain with obtained environmental DNA, which interferes downstream molecular analyses. To remedy this situation, two DNA extraction buffers (PIPES and Tris-HCl) and four purification strategies including our new modified low melting point gel purification method and three commercial kits from QIAEX, Omega and Promega were evaluated with diverse soil samples. The PIPES buffer (pH 6.5) is found to be more effective for removing the humic substances, but it leads to lower DNA yield and causes more severe DNA shearing than using the Tris-HCl buffer (pH 8.0). Gel purification and the Promega purification kit achieve much higher DNA recoveries than QIAEX or Omega kit, and higher purity of DNA is obtained by gel purification than by the Promega kit with both DNA extraction buffers mentioned above. Considering all results together, two alternative methods for DNA extraction and purification are proposed: one uses Tris-HCl buffer extraction and gel purification as the primary approach when the amount of soil or biomass is not a major concern, and the other uses PIPES buffer extraction and the Promega kit purification when severe DNA shearing and/or limited biomass occurs. Purified DNA samples by both methods are amenable for use as templates for whole community genome amplifications and PCR amplifications of bacterial 16S rRNA genes. It is demonstrated that these two alternative methods could be applied to a wide variety of environmental samples.

Elevated seawater temperature has altered the coupling between coastal primary production and heterotrophic bacterioplankton respiration. This shift, in turn, could influence the feedback of ocean ecosystem to climate warming. However, little is known about how natural bacterioplankton community responds to increasing seawater temperature. To investigate warming effects on the bacterioplankton community, we collected water samples from temperature gradients (ranged from 15.0 to 18.6 °C) created by a thermal flume of a coal power plant. The results showed that increasing temperatures significantly stimulated bacterial abundance, grazing rate, and altered bacterioplankton community compositions (BCCs). The spatial distribution of bacterioplankton community followed a distance similarity decay relationship, with a turnover of 0.005. A variance partitioning analysis showed that temperature directly constrained 2.01 % variation in BCCs, while temperature-induced changes in water geochemical and grazing rate indirectly accounted for 4.03 and 12.8 % of the community variance, respectively. Furthermore, the relative abundances of 24 bacterial families were linearly increased or decreased (P