Sample records for hmsr hmss hmst

  1. Knowledge-based personalized search engine for the Web-based Human Musculoskeletal System Resources (HMSR) in biomechanics.

    Dao, Tien Tuan; Hoang, Tuan Nha; Ta, Xuan Hien; Tho, Marie Christine Ho Ba


    Human musculoskeletal system resources of the human body are valuable for the learning and medical purposes. Internet-based information from conventional search engines such as Google or Yahoo cannot response to the need of useful, accurate, reliable and good-quality human musculoskeletal resources related to medical processes, pathological knowledge and practical expertise. In this present work, an advanced knowledge-based personalized search engine was developed. Our search engine was based on a client-server multi-layer multi-agent architecture and the principle of semantic web services to acquire dynamically accurate and reliable HMSR information by a semantic processing and visualization approach. A security-enhanced mechanism was applied to protect the medical information. A multi-agent crawler was implemented to develop a content-based database of HMSR information. A new semantic-based PageRank score with related mathematical formulas were also defined and implemented. As the results, semantic web service descriptions were presented in OWL, WSDL and OWL-S formats. Operational scenarios with related web-based interfaces for personal computers and mobile devices were presented and analyzed. Functional comparison between our knowledge-based search engine, a conventional search engine and a semantic search engine showed the originality and the robustness of our knowledge-based personalized search engine. In fact, our knowledge-based personalized search engine allows different users such as orthopedic patient and experts or healthcare system managers or medical students to access remotely into useful, accurate, reliable and good-quality HMSR information for their learning and medical purposes. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Reactor of the XXI century

    Zhotabaev, Zh.R.; Solov'ev, Yu.A.


    The advantages of both molten salt reactors (MSR) and homogenous molten salt reactors (HMSR) are illuminated. It is noted that the MSR possess accident probability A=10 -6 1/reactor.years and the HMSR with integral configuration has A=10 -7 1/reactor.years. The methods for these reactors technological problems solution - tritium removal, salt melt circulation and capacity pick up - are discussed

  3. Fur is a repressor of biofilm formation in Yersinia pestis.

    Fengjun Sun

    Full Text Available BACKGROUND: Yersinia pestis synthesizes the attached biofilms in the flea proventriculus, which is important for the transmission of this pathogen by fleas. The hmsHFRS operons is responsible for the synthesis of exopolysaccharide (the major component of biofilm matrix, which is activated by the signaling molecule 3', 5'-cyclic diguanylic acid (c-di-GMP synthesized by the only two diguanylate cyclases HmsT, and YPO0449 (located in a putative operonYPO0450-0448. METHODOLOGY/PRINCIPAL FINDINGS: The phenotypic assays indicated that the transcriptional regulator Fur inhibited the Y. pestis biofilm production in vitro and on nematode. Two distinct Fur box-like sequences were predicted within the promoter-proximal region of hmsT, suggesting that hmsT might be a direct Fur target. The subsequent primer extension, LacZ fusion, electrophoretic mobility shift, and DNase I footprinting assays disclosed that Fur specifically bound to the hmsT promoter-proximal region for repressing the hmsT transcription. In contrast, Fur had no regulatory effect on hmsHFRS and YPO0450-0448 at the transcriptional level. The detection of intracellular c-di-GMP levels revealed that Fur inhibited the c-di-GMP production. CONCLUSIONS/SIGNIFICANCE: Y. pestis Fur inhibits the c-di-GMP production through directly repressing the transcription of hmsT, and thus it acts as a repressor of biofilm formation. Since the relevant genetic contents for fur, hmsT, hmsHFRS, and YPO0450-0448 are extremely conserved between Y. pestis and typical Y. pseudotuberculosis, the above regulatory mechanisms can be applied to Y. pseudotuberculosis.

  4. Differential control of Yersinia pestis biofilm formation in vitro and in the flea vector by two c-di-GMP diguanylate cyclases.

    Yi-Cheng Sun


    Full Text Available Yersinia pestis forms a biofilm in the foregut of its flea vector that promotes transmission by flea bite. As in many bacteria, biofilm formation in Y. pestis is controlled by intracellular levels of the bacterial second messenger c-di-GMP. Two Y. pestis diguanylate cyclase (DGC enzymes, encoded by hmsT and y3730, and one phosphodiesterase (PDE, encoded by hmsP, have been shown to control biofilm production in vitro via their opposing c-di-GMP synthesis and degradation activities, respectively. In this study, we provide further evidence that hmsT, hmsP, and y3730 are the only three genes involved in c-di-GMP metabolism in Y. pestis and evaluated the two DGCs for their comparative roles in biofilm formation in vitro and in the flea vector. As with HmsT, the DGC activity of Y3730 depended on a catalytic GGDEF domain, but the relative contribution of the two enzymes to the biofilm phenotype was influenced strongly by the environmental niche. Deletion of y3730 had a very minor effect on in vitro biofilm formation, but resulted in greatly reduced biofilm formation in the flea. In contrast, the predominant effect of hmsT was on in vitro biofilm formation. DGC activity was also required for the Hms-independent autoaggregation phenotype of Y. pestis, but was not required for virulence in a mouse model of bubonic plague. Our results confirm that only one PDE (HmsP and two DGCs (HmsT and Y3730 control c-di-GMP levels in Y. pestis, indicate that hmsT and y3730 are regulated post-transcriptionally to differentially control biofilm formation in vitro and in the flea vector, and identify a second c-di-GMP-regulated phenotype in Y. pestis.

  5. Attempting to train a digital human model to reproduce human subject reach capabilities in an ejection seat aircraft

    Zehner, G.F.; Hudson, J.A.; Oudenhuijzen, A.


    From 1997 through 2002, the Air Force Research Lab and TNO Defence, Security and Safety (Business Unit Human Factors) were involved in a series of tests to quantify the accuracy of five Human Modeling Systems (HMSs) in determining accommodation limits of ejection seat aircraft. The results of these

  6. Hfq-dependent, co-ordinate control of cyclic diguanylate synthesis and catabolism in the plague pathogen Yersinia pestis.

    Bellows, Lauren E; Koestler, Benjamin J; Karaba, Sara M; Waters, Christopher M; Lathem, Wyndham W


    Yersinia pestis, the cause of the disease plague, forms biofilms to enhance flea-to-mammal transmission. Biofilm formation is dependent on exopolysaccharide synthesis and is controlled by the intracellular levels of the second messenger molecule cyclic diguanylate (c-di-GMP), but the mechanisms by which Y. pestis regulates c-di-GMP synthesis and turnover are not fully understood. Here we show that the small RNA chaperone Hfq contributes to the regulation of c-di-GMP levels and biofilm formation by modulating the abundance of both the c-di-GMP phosphodiesterase HmsP and the diguanylate cyclase HmsT. To do so, Hfq co-ordinately promotes hmsP mRNA accumulation while simultaneously decreasing the stability of the hmsT transcript. Hfq-dependent regulation of HmsP occurs at the transcriptional level while the regulation of HmsT is post-transcriptional and is localized to the 5' untranslated region/proximal coding sequence of the hmsT transcript. Decoupling HmsP from Hfq-based regulation is sufficient to overcome the effects of Δhfq on c-di-GMP and biofilm formation. We propose that Y. pestis utilizes Hfq to link c-di-GMP levels to environmental conditions and that the disregulation of c-di-GMP turnover in the absence of Hfq may contribute to the severe attenuation of Y. pestis lacking this RNA chaperone in animal models of plague. © 2012 Blackwell Publishing Ltd.

  7. Differential regulation of c-di-GMP metabolic enzymes by environmental signals modulates biofilm formation in Yersinia pestis

    Gai-Xian eRen


    Full Text Available Cyclic diguanylate (c-di-GMP is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs, HmsT and HmsD and one phosphodiesterase (PDE, HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD and HmsP in Y. pestis. Biofilm formation was higher in the presence of nonlethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfonate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulates their DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments.

  8. Facile and Scalable Synthesis of Monodispersed Spherical Capsules with a Mesoporous Shell

    Qi, Genggeng


    Monodispersed HMSs with tunable particle size and shell thickness were successfully synthesized using relatively concentrated polystyrene latex templates and a silica precursor in a weakly basic ethanol/water mixture. The particle size of the capsules can vary from 100 nm to micrometers. These highly engineered monodispersed capsules synthesized by a facile and scalable process may find applications in drug delivery, catalysis, separationm or as biological and chemical microreactors. © 2010 American Chemical Society.

  9. Avaliação nutricional da silagem de grãos úmidos de sorgo de alto ou de baixo conteúdo de tanino para frangos de corte Nutritional evaluation of high moisture sorghum silage grain with high or low tannin content for broilers

    Livia Carla Grigoletto Barcellos


    evaluate the moisture sorghum silage (HMSS with high or low tannin content as ingredient in broiler chicken diets. In the digestibility trial, ninety 20-d chicks were assigned to a completely randomized design with three treatments and six replications, and five chicks per experimental unit. Coefficients of metabolizable dry matter (MDM, metabolizable protein (MP, metabolizable starch (MS, metabolizable organic matter (MOM and metabolizable energy (ME of HMSS with high tannin, as-fed basis (66.22%DM, were as follows: 57.29; 56.96; 4.45; 35.27% and 2,408 kcal/kg, respectively. The coefficients of HMSS with low tannin were of 60.42; 59.95; 5.11; 39.58% and 2578 kcal/kg, respectively, as-fed basis (65.28% DM. In the performance assay, eight hundred and forty chicks were assigned to a completely randomized experimental design, with seven treatments, four replications and thirty chicks per experimental unit. Treatments consisted of a corn-soybean meal -based diet and six with 33, 66 and 100% HMSS with high or low content replaced by dry corn. Increasing HMSS levels with high tannin contents in diets caused a linear decrease on weight, weight gain, feed intake at 21 and 40 days old, but this effect was not observed for HMSS of low tannin content. Forty-day-old broilers fed diets with HMSS of high tannin content in 66 and 100% replacement levels showed lower weight and lower weigh gain. However, broilers fed HMSS with low tannin content did not differ from control. Linear decrease on the chicken leg color of was observed when HMSS was included in the diets. Performance results demonstrated that HMSS with high tannin content may replace um 33% of corn and with low tannin HMSS up to 100% of corn in diets of broilers, with no effect on performance and with lower cost per kilogram of produced broiler.

  10. Helmet Sensor - Transfer Function and Model Development


    that helmets be examined forensically when estimating the impact direction and location and the electronic HMSS data not be used in that determination... forensic analysis of the helmet itself is therefore recommended to determine the direction and severity of the ballistic impact 5. The helmet shell does...ot83 HTI l ot 8J HT1 lot S ,HTt IOt S , HTI l otiH HTt lotSS HTt l vt85 HTI l o)t 85 HT1 Front Level Acceleration ~~,--~----~--,30’p~g

  11. A four-functional composite-hierarchical anatase TiO2 microsphere consisting of nanoparticles, nanowires and submicron ellipsoidal spheres for Dye Sensitized Solar Cells

    Huang, Niu; Chen, Feitai; Sun, Panpan; Sun, Xiaohua; Sebo, Bobby; Zhao, Xingzhong


    Graphical abstract: - Abstract: In this paper, we prepare a composite-hierarchical microsphere (HMS) which is composed of two kinds of HMSs: one flower-like microsphere (FMS, ∼1.5 μm, containing nanoparticles and nanowires) and plentiful mesoporous submicron ellipsoidal spheres (ESs, ∼200 nm, assembled with nanoparticles) which are embedded evenly in the FMS. For comparing, pure FMS and ES are prepared, respectively. It is found that the composite-HMS possesses (a) the highest BET surface area, (b) the highest light scattering ability, (c) the fastest electron transport and the longest electron life time, and (d) light trapping ability enabled by multiple light reflection and scattering between ESs and nanowires inside each FMS*ESs particle. The energy conversion efficiency of 7.91% of the DSSC based on FMS*ESs is higher than devices based on ES and FMS (7.22% and 7.24%, respectively), which also benefits from the structural advantages of the composite-HMS compared with non-composite HMSs

  12. Structural, optical, and magnetic studies of manganese-doped zinc oxide hierarchical microspheres by self-assembly of nanoparticles.

    Hao, Yao-Ming; Lou, Shi-Yun; Zhou, Shao-Min; Yuan, Rui-Jian; Zhu, Gong-Yu; Li, Ning


    In this study, a series of manganese [Mn]-doped zinc oxide [ZnO] hierarchical microspheres [HMSs] are prepared by hydrothermal method only using zinc acetate and manganese acetate as precursors and ethylene glycol as solvent. X-ray diffraction indicates that all of the as-obtained samples including the highest Mn (7 mol%) in the crystal lattice of ZnO have a pure phase (hexagonal wurtzite structure). A broad Raman spectrum from as-synthesized doping samples ranges from 500 to 600 cm-1, revealing the successful doping of paramagnetic Mn2+ ions in the host ZnO. Optical absorption analysis of the samples exhibits a blueshift in the absorption band edge with increasing dopant concentration, and corresponding photoluminescence spectra show that Mn doping suppresses both near-band edge UV emission and defect-related blue emission. In particular, magnetic measurements confirm robust room-temperature ferromagnetic behavior with a high Curie temperature exceeding 400 K, signifying that the as-formed Mn-doped ZnO HMSs will have immense potential in spintronic devices and spin-based electronic technologies.

  13. Design of high-gain, wideband antenna using microwave hyperbolic metasurface

    Zhao, Yan, E-mail: [International School of Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand)


    In this work, we apply hyperbolic metasurfaces (HMSs) to design high-gain and wideband antennas. It is shown that HMSs formed by a single layer of split-ring resonators (SRRs) can be excited to generate highly directive beams. In particular, we suggest two types of the SRR-HMS: a capacitively loaded SRR (CLSRR)-HMS and a substrate-backed double SRR (DSRR)-HMS. Both configurations ensure that the periodicity of the structures is sufficiently small for satisfying the effective medium theory. For the antenna design, we propose a two-layer-stacked configuration for the 2.4 GHz frequency band based on the DSRR-HMS excited by a folded monopole. Measurement results confirm numerical simulations and demonstrate that an antenna gain of more than 5 dBi can be obtained for the frequency range of 2.1 - 2.6 GHz, with a maximum gain of 7.8 dBi at 2.4 GHz.

  14. Avaliação nutricional da silagem de grãos úmidos de sorgo de alto ou de baixo conteúdo de taninos para leitões na fase de creche Nutritional evaluation of high moisture sorghum silage grain of high or low tannin contents for nursery piglets

    Valquiria Mayumi Ishida Patricio


    (HMSS of high or low tannin contents for piglets. In the digestibility trial, twelve crossbred, castrated males, averaging initial body weight of 15.9±1.9 kg were allotted to metabolism cages, as a completely randomized design, with four experimental units and one piglet per cage. The total feces and urine collection method was used. The values of digestible DM, digestible protein, digestible starch, digestible OM, digestible energy and ME of HMSS of high tannin were, respectively, of 43.94, 5.45, 46.67, 63.46%, 2,700, and 2,674 kcal/kg and of HMSS of low tannin were of 40.72, 5.92, 44.08, 63.75%, 2,641, and 2,608 kcal/kg respectively, as-fed basis (68.75% DM. The second trial was carried out to evaluate piglet performance and economic viability of diets with different dry yellow corn replacement levels with HMSS of high or low tannin contents. Fifty-six crossbred piglets (14.7±1.9 and 29.2±3.0 kg initial and final body weight were allotted to four treatments as a completely randomized design, with four experimental units of two piglets. The treatments consisted of a basal corn-soybean meal based diet and six diets of dry corn replacement with 33, 66, and 100% of HMSS of high or low tannin contents based on the digestible energy contents of these feedstuffs. No treatment effect on piglet performance was observed, however, there was linear increasing effect on daily feed intake for HMSS of low tannin and linear decreasing effect for diet cost per kilogram of weight gain for HMSS of high tannin.

  15. Immunoglobulin variable region sequences of two human monoclonal antibodies directed to an onco-developmental carbohydrate antigen, lactotetraosylceramide (LcOse4Cer).

    Yago, K; Zenita, K; Ohwaki, I; Harada, R; Nozawa, S; Tsukazaki, K; Iwamori, M; Endo, N; Yasuda, N; Okuma, M


    A human monoclonal antibody, 11-50, was generated and was shown to recognize an onco-developmental carbohydrate antigen, LcOse4Cer. The isotype of this antibody was IgM, lambda, similar to the previously known human anti-LcOse4 antibodies, such as IgMWOO and HMST-1. We raised a murine anti-idiotypic antibody G3 (IgG1, kappa) against 11-50, and tested its reactivity towards the affinity purified human polyclonal anti-LcOse4 antibodies prepared from pooled human sera using a Gal beta 1-->3GlcNAc beta-immobilized column. The results indicated that at least a part of the human polyclonal anti-LcOse4 antibodies shared the G3 idiotype with 11-50. We further analyzed the sequence of variable regions of the two anti-LcOse4 antibodies, 11-50 and HMST-1. Sequence analysis of the heavy chain variable regions indicated that the VH regions of these two antibodies were highly homologous to each other (93.5% at the nucleic acid level), and these antibodies utilized the germline genes VH1.9III and hv3005f3 as the VH segments, which are closely related germline genes of the VHIII family. It was noted that these germline VH genes are frequently utilized in fetal B cells. The JH region of both antibodies was encoded by the JH4 gene. For the light chain, the V lambda segments of the two antibodies were 96.3% homologous to each other at the nucleic acid level. The V lambda segments of both antibodies showed the highest homology to the rearranged V lambda gene called V lambda II.DS among reported V lambda genes, while the exact germline V lambda genes encoding the two antibodies were not yet registered in available sequence databanks. The amino acid sequences of the J lambda segments of both antibodies were identical. These results indicate that the two human antibodies recognizing the onco-developmental carbohydrate antigen Lc4 are encoded by the same or very homologous germline genes.

  16. Desempenho e digestibilidade de nutrientes em frangos de corte alternativos alimentados com silagem de grãos úmidos de sorgo - DOI: 10.4025/actascianimsci.v29i3.557 Performance and nutrient digestibility in alternative broilers fed with high-moisture sorghum grains silage - DOI: 10.4025/actascianimsci.v29i3.557

    Vanessa Cristina Pelícia


    Full Text Available O objetivo do trabalho foi avaliar os níveis de inclusão de silagem de grãos úmidos de sorgo (SGUS, em substituição ao milho seco da ração sobre desempenho, rendimento de carcaça, cortes e gordura abdominal, além de avaliação econômica da criação alternativa, no período de 1 a 49 dias de idade. Também foi avaliada a digestibilidade das rações aos 21 dias de idade. Para as análises de desempenho e rendimento de carcaça, foram distribuídos, em galpão, 600 pintos machos (Cobb, um dia de idade, em delineamento em blocos casualizados, com seis tratamentos (0, 10, 20, 30, 40 e 50% de inclusão SGUS, em substituição ao milho seco da ração, e quatro repetições de 25 aves cada. Para digestibilidade, foram alojados em câmara termoneutra, 72 pintos (Cobb, em 24 gaiolas, sendo três aves/gaiola, 12 aves/tratamento. Os tratamentos experimentais foram os mesmos adotados para o galpão. A SGUS pode substituir em até 50% o milho seco das rações de frangos alternativos, criados até 49 dias de idade, sem alterar desempenho, rendimento de carcaça, cortes e gordura abdominal, bem como a digestibilidade de nutrientes aos 21 dias de idade. Entretanto, o maior retorno econômico e melhor fator de produção foram obtidos com 10% de substituição.The objective of this study was to evaluate levels of inclusion of high-moisture sorghum grains silage (HMSS in replacement of dry corn in diet on performance, carcass yield, cuts and abdominal fat, and also economic analysis of alternative system at 1 to 49 d of age. The digestibility of the diets was determined at 21 d of age. For performance and carcass yield analysis, 600 one-day-old male broiler chicks (Cobb were used, installed in a broiler house, in a randomized blocks, with six treatments based on the inclusion of 0, 10, 20, 30, 40 and 50% of HMSS in replacement of dry corn, and four replicates/treatment with 25 chicks each. For digestibility, 72 one-dayold male chicks (Cobb were

  17. Regulation of Biofilm Formation by Hfq is Influenced by Presence of Plasmid pCD1 in Yersinia Pestis Biovar Microtus

    Huiying Yang


    Full Text Available Yersinia pestis synthesizes the attached biofilms in the flea gut to promotethe flea-borne transmission of this deadly pathogen. Bellows et al. reported that the posttranscriptional regulator Hfq inhibites biofilm formation in apCD1− derivative of Y. pestis CO92, however, we found that Hfq stimulates biofilm production in a microtus strain of Y. pestis with the typical plasmids, including pCD1. When we cured pCD1 from this strain, the biofilm phenotype was in accordance with that reported by Bellows et al., indicating that the unknown pCD1-associated factors modulating the regulatory pathways of Y. pestis biofilm formation. Further gene regulation experiments using relevant pCD1+ Y. pestis strains disclose that Hfq positively regulates the expression of hmsHFRS and hmsT encoding a diguanylate cyclase while negatively regulates the expression of hmsP encoding the sole phosphodiesterase. However, Hfq has no regulatory effect on the expression of hmsCDE at the mRNA and protein levels. Our results suggest that we should be cautious to make conclusion from results based on the pCD1-cured Y. pestis.

  18. Analysis of iron acquisition and storage-related genes in clinical and non-clinical strains of Yersinia enterocolitica biovar 1A.

    Kanaujia, Pawan Kumar; Bajaj, Priyanka; Virdi, Jugsharan Singh


    Possession of mechanisms for iron acquisition and its storage enhances the ability of the bacteria to survive in the iron-limiting environment of the host. In this study, 81 strains of Yersinia enterocolitica biovar 1A isolated from various clinical (n = 51) and non-clinical (n = 30) sources were investigated for the presence of the genes related to iron acquisition and storage. Important genes which were present in more than 85% of the strains included hasA, foxA, bfr, bfd, ftnA, and hmsT as well as the fhuCDB, fepBDGCfesfepA, feoAB, yfuABCD, hemPRSTUV, and hmsHFRS gene clusters. Majority of these genes is being reported for the first time in biovar 1A strains and showed significant homology with genes present in the known pathogenic biovars of Y. enterocolitica. However, no significant difference was observed in the distribution of iron acquisition and storage-related genes among clinical and non-clinical biovar 1A strains. Thus, it may be suggested that the presence of iron acquisition and storage-related genes per se might not be responsible for the supposedly better ability of clinical biovar 1A strains to cause infections in humans. However, in the backdrop of this data, the need to undertake functional studies are highly recommended. © 2015 APMIS. Published by John Wiley & Sons Ltd.

  19. The Role of Consumer-Controlled Personal Health Management Systems in the Evolution of Employer-Based Health Care Benefits.

    Jones, Spencer S; Caloyeras, John; Mattke, Soeren


    The passage of the Patient Protection and Affordable Care Act has piqued employers' interest in new benefit designs because it includes numerous provisions that favor cost-reducing strategies, such as workplace wellness programs, value-based insurance design (VBID), and consumer-directed health plans (CDHPs). Consumer-controlled personal health management systems (HMSs) are a class of tools that provide encouragement, data, and decision support to individuals. Their functionalities fall into the following three categories: health information management, promotion of wellness and healthy lifestyles, and decision support. In this study, we review the evidence for many of the possible components of an HMS, including personal health records, web-based health risk assessments, integrated remote monitoring data, personalized health education and messaging, nutrition solutions and physical activity monitoring, diabetes-management solutions, medication reminders, vaccination and preventive-care applications, integrated incentive programs, social-networking tools, comparative data on price and value of providers, telehealth consultations, virtual coaching, and an integrated nurse hotline. The value of the HMS will be borne out as employers begin to adopt and implement these emerging technologies, enabling further assessment as their benefits and costs become better understood.

  20. CRP-Mediated Carbon Catabolite Regulation of Yersinia pestis Biofilm Formation Is Enhanced by the Carbon Storage Regulator Protein, CsrA.

    Stephan P Willias

    Full Text Available The natural transmission of Yersinia pestis is reliant upon biofilm blockage of the flea vector. However, the environmentally-responsive adaptive regulators which facilitate Y. pestis biofilm production in accordance with the flea midgut milieu are not well understood. We seek to establish the impact of available carbon source metabolism and storage upon Y. pestis biofilm production. Our findings demonstrate that Y. pestis biofilm production is subject to carbon catabolite regulation in which the presence of glucose impairs biofilm production; whereas, the sole metabolism of alternate carbon sources promotes robust biofilm formation. This observation is facilitated by the cAMP receptor protein, CRP. In accordance with a stark growth defect, deletion of crp in both CO92 and KIM6+ Y. pestis strains significantly impaired biofilm production when solely utilizing alternate carbon sources. Media supplementation with cAMP, a small-molecule activator of CRP, did not significantly alter Y. pestis biofilm production. Furthermore, CRP did not alter mRNA abundance of previously-characterized hms biofilm synthesis and regulation factors. Therefore, our findings indicate CRP does not confer a direct stimulatory effect, but may indirectly promote Y. pestis biofilm production by facilitating the alternate carbon source expression profile. Additionally, we assessed the impact of the carbon storage regulator protein, CsrA, upon Y. pestis biofilm production. Contrary to what has been described for E. coli, Y. pestis biofilm formation was found to be enhanced by CsrA. Regardless of media composition and available carbon source, deletion of csrA significantly impaired Y. pestis biofilm production. CsrA was found to promote Y. pestis biofilm production independent of glycogen regulation. Loss of csrA did not significantly alter relative hmsH, hmsP, or hmsT mRNA abundance. However, deletion of hmsP in the csrA-deficient mutant enabled excessive biofilm production