Effects of local and global stressors on the status and future persistence of intertidal canopy-forming algae

Marine canopy-forming seaweeds are among the most important habitat-forming species along temperate and polar rocky coasts. They form diverse, productive and valuable "forest" habitats that play a key role in coastal primary production, nutrient cycling and disturbance regulation, and facilitate abundant algae and animal communities. They are also some of the most heavily impacted coastal habitats, facing increasing pressures from urban sprawl, pollution, overfishing and climatic instabilities. Identifying the type and strength of interactions between multiple anthropogenic and natural stressors can help setting achievable management targets for degraded ecosystems and support ecological resilience through local actions. My research focuses primarily on understanding the effects of multiple local and global stressors on canopy-forming seaweeds of the genus Cystoseira, with and emphasis on field investigation and experimentation. I approached my research integrating different approaches: 1) I investigated which are the factors driving the loss of canopy-forming seaweeds at global level. The results allowed to detect important synergistic interactions between nutrient enrichment, caused mainly by human activities, and different other stressors such as heavy metals, the presence of competitors, low light and increasing temperature. This suggested that local management of nutrient levels would provide the greatest opportunity for preventing the shift from canopy to mat-forming algae; 2) as second step, I analysed the status of the intertidal Cystoseira populations around the Italian coast, and explored which factors are most likely to influence it. The results reported severe depletion of intertidal populations of Cystoseira, and identified urbanization as one of the main factors related to these poor conditions, confirming the need for urgent management actions to reduce human pressures on these valuable habitat forming species; 3) then, I experimentally investigated the effects of extreme events caused by climate change. I focused my attention on the effects of abrupt increases of air temperature caused by heat-wave events on the intertidal C. compressa around the Italian coast. The results indicated that extreme heat-wave negatively affect the photosynthetic activity of C. compressa, and that local biodiversity and thermal history of the alga seem to play a role reducing or increasing respectively the impact of such extreme events. 4) I also explored the possible overlooked role of the epiphytic bacteria growing on C. compressa. Bacteria can interact with seaweeds in symbiotic, pathological and opportunistic ways, modulating the health, performance and resilience of their hosts and could, therefore play a critical role on the responses of Cystoseira spp. to stress factors. I characterised for the first time the epiphytic bacteria associated to the surface of C. compressa using Illumina Miseq sequences of V1-V3 hypervariable regions of 16S rRNA gene, and investigated their seasonal variations and their relationships with the bacterial populations in the surrounding seawater. I found that bacterial populations associated to C. compressa were clearly distinct from those in the surrounding media, and identified a clear successional pattern, interestingly characterized by an increase in abundance of potential microbial pathogens associated to older thalli of C. compressa; 5) the previous quantitative descriptive work represented an important base-knowledge to further explore experimentally whether surface bacteria could influence the responses of their hosting Cystoseira populations to stressors. I analysed experimentally in the field the interacting effects of nutrient enrichment and heat-wave events on C. compressa population, and explored whether any resulting changes in the photosynthetic activity of C. compressa were associated to changes in the epiphytic bacterial communities. The heat wave caused marked declines of the photosynthetic activity of the intertidal C. compressa. These effects persisted for at least 3 hours, while recovery generally occurred after 24 hours. The heat-wave altered the structure of the epiphytic bacteria of C. compressa. Thalli exposed to the heat-wave presented an increase of OTUs previously shown to be associated with the natural degradation of the thalli of C. compressa, or implied in causing disease or damage to macroalgae. As observed for the photosynthetic activity, these differences decreased over time, suggesting that the microbial community has the ability to recover. Differently from previous work, this experiment did not detect significant effects related to nutrient enrichment, suggesting that the effects of nutrients could be context dependent. These results open new questions concerning the mechanisms by which the epibacterial community could influence the responses and future persistence of these important canopy-forming seaweeds

Request-peer selection for load-balancing in P2P live streaming systems

Theme: Services, Applications and BusinessUnlike peer-to-peer (P2P) file sharing, P2P live streaming systems have to meet real-time playback constraints, which makes it very challenging yet crucial to maximize the peer uplink bandwidth utilization so as to deliver content pieces in time. In general, this is achieved by adopting tailor-made piece selection and request-peer selection algorithms. The design philosophy is to regulate the network traffic and to balance the load among peers. In this paper, we propose a new request-peer selection algorithm. In particular, a peer in the network estimates the service response time (SRT) between itself and each neighboring peer. An SRT is measured from when a data piece request is sent until the requested piece arrives. When a peer makes a piece request, the neighbor with smaller SRT and fewer data pieces would be favored among potential providers. This is because smaller SRT implies excess serving capacity and fewer data pieces suggests less piece requests received. We evaluate the performance of our request-peer selection algorithm through extensive packet level simulations. Our simulation results show that the traffic load in the network is better balanced in the sense that the difference of the normalized number of data packets uploaded by each peer is getting smaller and the number of repeated piece requests generated by each peer (due to request failure) is significantly reduced. We also found that the load of streaming server is reduced, and the overall quality of service, measured by playback continuity, startup delay etc, is improved as well. © 2012 IEEE.published_or_final_versio

Genetic diversity of Escherichia coli isolated from commercial swine farms revealed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and repetitive extragenic palindrome PCR (REP-PCR)

The objective of this study was to use enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and repetitive extragenic palindrome PCR (REP-PCR) for the analysis of genetic diversity among Escherichia coli strains isolated from commercial swine farms in Sichuan province of China. Thirty four strains of E. coli were selected by selective medium and conventional biochemical test from fresh stool samples of swines in five farms in Sichuan province. The isolates were identified by 160 kinds of E. coli O serums. The results show that 30 strains were determined among 34 E. coli isolates, 12 kinds of O serogroups were obtained on the basis of the agglutination test. The predominant types are O23, O113 and O120, representing 35.4%. Furthermore, the genotypes and phylogenetic relationship of all isolates were analysed by Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and repetitive extragenic palindrome PCR (REP-PCR), 34 E. coli isolates were clustered to 19 ERIC-PCR genotypes and 13 REP-PCR genotypes. The isolates from the same farm or sharing the same serotyping showed different genotype. And the isolates which could not be serotyped were genotyped by ERIC-PCR and REP-PCR. The analysis of genetic type and original source revealed that isolates from different farms had different genetic types. The subtypes of E. coli are also different within a single farm. Genetic variability with E. coli strains isolated from swine farms in China has been demonstrated. The presence of ERIC-PCR and REP-PCR sequences in the genome of E. coli was confirmed. ERIC-PCR and REP-PCR techniques are more rapid methods for molecular typing of E. coli strain. They are also useful methods for diversity survey of E. coli and the two methods analyzes genetic diversity of E. coli isolated in Sichuan of China.Key words: Escherichia coli, serotype, enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), repetitive extragenic palindrome PCR (REP-PCR)

Hormonal regulation of ovarian bursa fluid in mice and involvement of aquaporins.

In rodent species, the ovary and the end of oviduct are encapsulated by a thin membrane called ovarian bursa. The biological functions of ovarian bursa remain unexplored despite its structural arrangement in facilitating oocytes transport into oviduct. In the present study, we observed a rapid fluid accumulation and reabsorption within the ovarian bursa after ovarian stimulation (PMSG-primed hCG injection), suggesting that the ovarian bursa might play an active role in regulating local fluid homeostasis around the timing of ovulation. We hypothesized that the aquaporin proteins, which are specialized channels for water transport, might be involved in this process. By screening the expression of aquaporin family members (Aqp1-9) in the ovarian tissue and isolated ovarian bursa (0, 1, 2 and 5 h after hCG injection), we found that AQP2 and AQP5 mRNA showed dynamic changes after hCG treatment, showing upregulation at 1-2 h followed by gradually decrease at 5 h, which is closely related with the intra-bursa fluid dynamics. Further immunofluorescence examinations of AQP2 and AQP5 in the ovarian bursa revealed that AQP2 is specifically localized in the outer layer (peritoneal side) while AQP5 localized in the inner layer (ovarian side) of the bursa, such cell type specific and spatial-temporal expressions of AQP2 and 5 support our hypothesis that they might be involved in efficient water transport through ovarian bursa under ovulation related hormonal regulation. The physiological significance of aquaporin-mediated water transport in the context of ovarian bursa still awaits further clarification

Intervention effects of Ganoderma lucidum spores on epileptiform discharge hippocampal neurons and expression of Neurotrophin-4 and N-Cadherin

Epilepsy can cause cerebral transient dysfunctions. Ganoderma lucidum spores (GLS), a traditional Chinese medicinal herb, has shown some antiepileptic effects in our previous studies. This was the first study of the effects of GLS on cultured primary hippocampal neurons, treated with Mg2+ free medium. This in vitro model of epileptiform discharge hippocampal neurons allowed us to investigate the anti-epileptic effects and mechanism of GLS activity. Primary hippocampal neurons from <1 day old rats were cultured and their morphologies observed under fluorescence microscope. Neurons were confirmed by immunofluorescent staining of neuron specific enolase (NSE). Sterile method for GLS generation was investigated and serial dilutions of GLS were used to test the maximum non-toxic concentration of GLS on hippocampal neurons. The optimized concentration of GLS of 0.122 mg/ml was identified and used for subsequent analysis. Using the in vitro model, hippocampal neurons were divided into 4 groups for subsequent treatment i) control, ii) model (incubated with Mg2+ free medium for 3 hours), iii) GLS group I (incubated with Mg2+ free medium containing GLS for 3 hours and replaced with normal medium and incubated for 6 hours) and iv) GLS group II (neurons incubated with Mg2+ free medium for 3 hours then replaced with a normal medium containing GLS for 6 hours). Neurotrophin-4 and N-Cadherin protein expression were detected using Western blot. The results showed that the number of normal hippocampal neurons increased and the morphologies of hippocampal neurons were well preserved after GLS treatment. Furthermore, the expression of neurotrophin-4 was significantly increased while the expression of N-Cadherin was decreased in the GLS treated group compared with the model group. This data indicates that GLS may protect hippocampal neurons by promoting neurotrophin-4 expression and inhibiting N-Cadherin expression

Structure of hadron resonances with a nearby zero of the amplitude

We discuss the relation between the analytic structure of the scattering amplitude and the origin of an eigenstate represented by a pole of the amplitude.If the eigenstate is not dynamically generated by the interaction in the channel of interest, the residue of the pole vanishes in the zero coupling limit. Based on the topological nature of the phase of the scattering amplitude, we show that the pole must encounter with the Castillejo-Dalitz-Dyson (CDD) zero in this limit. It is concluded that the dynamical component of the eigenstate is small if a CDD zero exists near the eigenstate pole. We show that the line shape of the resonance is distorted from the Breit-Wigner form as an observable consequence of the nearby CDD zero. Finally, studying the positions of poles and CDD zeros of the KbarN-piSigma amplitude, we discuss the origin of the eigenstates in the Lambda(1405) region.Comment: 7 pages, 3 figures, v2: published versio

Monocytes of patients with familial hypercholesterolemia show alterations in cholesterol metabolism

<p>Abstract</p> <p>Background</p> <p>Elevated plasma cholesterol promotes the formation of atherosclerotic lesions in which monocyte-derived lipid-laden macrophages are frequently found. To analyze, if circulating monocytes already show increased lipid content and differences in lipoprotein metabolism, we compared monocytes from patients with Familial Hypercholesterolemia (FH) with those from healthy individuals.</p> <p>Methods</p> <p>Cholesterol and oxidized cholesterol metabolite serum levels of FH and of healthy, gender/age matched control subjects were measured by combined gas chromatography – mass spectroscopy. Monocytes from patients with FH and from healthy subjects were isolated by antibody-assisted density centrifugation. Gene expression profiles of isolated monocytes were measured using Affymetrix HG-U 133 Plus 2.0 microarrays. We compared monocyte gene expression profiles from FH patients with healthy controls using a Welch T-test with correction for multiple testing (p < 0.05; Benjamini Hochberg correction, False Discovery Rate = 0.05). The differential expression of FH associated genes was validated at the mRNA level by qRT-PCR and/or at the protein level by Western Blot or flow cytometry. Functional validation of monocyte scavenger receptor activities were done by binding assays and dose/time dependent uptake analysis using native and oxidized LDL.</p> <p>Results</p> <p>Using microarray analysis we found in FH patients a significant up-regulation of 1,617 genes and a down-regulation of 701 genes compared to monocytes from healthy individuals. These include genes of proteins that are involved in the uptake, biosynthesis, disposition, and cellular efflux of cholesterol. In addition, plasma from FH patients contains elevated amounts of sterols and oxysterols. An increased uptake of oxidized as well as of native LDL by FH monocytes combined with a down-regulation of NPC1 and ABCA1 explains the lipid accumulation observed in these cells.</p> <p>Conclusion</p> <p>Our data demonstrate that circulating FH monocytes show differences in cell physiology that may contribute to the early onset of atherosclerosis in this disease.</p

The N-terminus of FILIA Forms an Atypical KH Domain with a Unique Extension Involved in Interaction with RNA

FILIA is a member of the recently identified oocyte/embryo expressed gene family in eutherian mammals, which is characterized by containing an N-terminal atypical KH domain. Here we report the structure of the N-terminal fragment of FILIA (FILIA-N), which represents the first reported three-dimensional structure of a KH domain in the oocyte/embryo expressed gene family of proteins. The structure of FILIA-N revealed a unique N-terminal extension beyond the canonical KH region, which plays important roles in interaction with RNA. By co-incubation with the lysates of mice ovaries, FILIA and FILIA-N could sequester specific RNA components, supporting the critical roles of FILIA in regulation of RNA transcripts during mouse oogenesis and early embryogenesis

Prediction of 3D grinding temperature field based on meshless method considering infinite element

© 2018, Springer-Verlag London Ltd., part of Springer Nature. A three-dimensional numerical model to calculate the grinding temperature field distribution is presented. The finite block method, which is developed from meshless method, is used to deal with the stationary and the transient heat conduction problems in this paper. The influences of workpiece feed velocity, cooling coefficient, and the depth of cut on temperature distribution are considered. The model with temperature-dependent thermal conductivity and specific heat is presented. The Lagrange partial differential matrix from the heat transfer governing equation is obtained by using Lagrange series and mapping technique. The grinding wheel-workpiece contact area is assumed as a moving distributed square heat source. The Laplace transformation method and Durbin’s inverse technique are employed in the transient heat conduction analysis. The results of the developed model are compared with others’ finite element method solutions and analytical solutions where a good agreement is demonstrated. And the finite block method was proved a better convergence and accuracy than finite element method by comparing the ABAQUS results. In addition, the three-dimensional infinite element is introduced to perform the thermal analysis, and there is a great of advantages in the simulation of large boundary problems.The work was funded by China Scholarship Council, the Fundamental Research Funds for the Central Universities (N160306006), National Natural Science Foundation of China (51275084), and Science and technology project of Shenyang (18006001)

SLC11A1 (NRAMP1) Polymorphisms and Tuberculosis Susceptibility: Updated Systematic Review and Meta-Analysis

Background: Natural resistance associated macrophage protein 1 (NRAMP1), encoded by the SLC11A1 gene, has been described to regulate macrophage activation and be associated with infectious and autoimmune diseases. The relation between SLC11A1 polymorphisms and tuberculosis susceptibility has been studied in different populations. Methods: We systematically reviewed published studies on SLC11A1 polymorphisms and tuberculosis susceptibility until September 15, 2010 and quantitatively summarized associations of the most widely studied polymorphisms using metaanalysis. Results: In total, 36 eligible articles were included in this review. In Meta-analysis, significant associations were observed between tuberculosis risk and widely studied SLC11A1 polymorphisms with summarized odds ratio of 1.35 (95%CI, 1.17– 1.54), 1.25 (95 % CI, 1.04–1.50), 1.23 (95 % CI, 1.04–1.44), 1.31 (95%CI, 1.08–1.59) for 39 UTR, D543N, INT4, and 59 (GT)n, respectively. Heterogeneity between studies was not pronounced, and the associations did not remarkably vary in the stratified analysis with respect to study population and study base. Conclusions: The association between SLC11A1 polymorphisms and tuberculosis susceptibility observed in our analyses supports the hypothesis that NRAMP1 might play an important role in the host defense to the development of tuberculosis