Manipulation of pH Shift to Enhance the Growth and Antibiotic Activity of Xenorhabdus nematophila

To evaluate the effects of pH control strategy on cell growth and the production of antibiotic (cyclo(2-Me-BABA-Gly)) by Xenorhabdus nematophila and enhance the antibiotic activity. The effects of uncontrolled- (different initial pH) and controlled-pH (different constant pH and pH-shift) operations on cell growth and antibiotic activity of X. nematophila YL00I were examined. Experiments showed that the optimal initial pH for cell growth and antibiotic production of X. nematophila YL001 occurred at 7.0. Under different constant pH, a pH level of 7.5 was found to be optimal for biomass and antibiotic activity at 23.71 g/L and 100.0 U/mL, respectively. Based on the kinetic information relating to the different constant pH effects on the fermentation of X. nematophila YL001, a two-stage pH control strategy in which pH 6.5 was maintained for the first 24 h, and then switched to 7.5 after 24 h, was established to improve biomass production and antibiotic activity. By applying this pH-shift strategy, the maximal antibiotic activity and productivity were significantly improved and reaching 185.0 U/mL and 4.41 U/mL/h, respectively, compared to values obtained from constant pH operation (100.0 U/mL and 1.39 U/mL/h)

Improvement of antibiotic activity of Xenorhabdus bovienii by medium optimization using response surface methodology

<p>Abstract</p> <p>Background</p> <p>The production of secondary metabolites with antibiotic properties is a common characteristic to entomopathogenic bacteria <it>Xenorhabdus</it> spp. These metabolites not only have diverse chemical structures but also have a wide range of bioactivities with medicinal and agricultural interests such as antibiotic, antimycotic and insecticidal, nematicidal and antiulcer, antineoplastic and antiviral. It has been known that cultivation parameters are critical to the secondary metabolites produced by microorganisms. Even small changes in the culture medium may not only impact the quantity of certain compounds but also the general metabolic profile of microorganisms. Manipulating nutritional or environmental factors can promote the biosynthesis of secondary metabolites and thus facilitate the discovery of new natural products. This work was conducted to evaluate the influence of nutrition on the antibiotic production of <it>X. bovienii</it> YL002 and to optimize the medium to maximize its antibiotic production.</p> <p>Results</p> <p>Nutrition has high influence on the antibiotic production of <it>X. bovienii</it> YL002. Glycerol and soytone were identified as the best carbon and nitrogen sources that significantly affected the antibiotic production using one-factor-at-a-time approach. Response surface methodology (RSM) was applied to optimize the medium constituents (glycerol, soytone and minerals) for the antibiotic production of <it>X. bovienii</it> YL002. Higher antibiotic activity (337.5 U/mL) was obtained after optimization. The optimal levels of medium components were (g/L): glycerol 6.90, soytone 25.17, MgSO₄·7H₂O 1.57, (NH₄)₂SO₄ 2.55, KH₂PO₄ 0.87, K₂HPO₄ 1.11 and Na₂SO₄ 1.81. An overall of 37.8% increase in the antibiotic activity of <it>X. bovienii</it> YL002 was obtained compared with that of the original medium.</p> <p>Conclusions</p> <p>To the best of our knowledge, there are no reports on antibiotic production of <it>X. boviebii</it> by medium optimization using RSM. The results strongly support the use of RSM for medium optimization. The optimized medium not only resulted in a 37.8% increase of antibiotic activity, but also reduced the numbers of experiments. The chosen method of medium optimization was efficient, simple and less time consuming. This work will be useful for the development of <it>X. bovienii</it> cultivation process for efficient antibiotic production on a large scale, and for the development of more advanced control strategies on plant diseases.</p

The estimation of vehicle speed and stopping distance by pedestrians crossing streets in a naturalistic traffic environment

The ability to estimate vehicle speed and stopping distance accurately is important for pedestrians to make safe road crossing decisions. In this study, a field experiment in a naturalistic traffic environment was conducted to measure pedestrians&#39; estimation of vehicle speed and stopping distance when they are crossing streets. Forty-four participants (18-45 years old) reported their estimation on 1043 vehicles, and the corresponding actual vehicle speed and stopping distance were recorded. In the speed estimation task, pedestrians&#39; performances change in different actual speed levels and different weather conditions. In sunny conditions, pedestrians tended to underestimate actual vehicle speeds that were higher than 40 km/h but were able to accurately estimate speeds that were lower than 40 km/h. In rainy conditions, pedestrians tended to underestimate actual vehicle speeds that were higher than 45 km/h but were able to accurately estimate speeds ranging from 35 km/h to 45 km/h. In stopping distance estimation task, the accurate estimation interval ranged from 60 km/h to 65 km/h, and pedestrians generally underestimated the stopping distance when vehicles were travelling over 65 km/h. The results show that pedestrians have accurate estimation intervals that vary by weather conditions. When the speed of the oncoming vehicle exceeded the upper bound of the accurate interval, pedestrians were more likely to underestimate the vehicle speed, increasing their risk of incorrectly deciding to cross when it is not safe to do so. (C) 2015 Elsevier Ltd. All rights reserved.</p

Detection of the four major human herpesviruses simultaneously in whole blood and cerebrospinal fluid samples by the fluorescence polarization assay

SummaryObjectivesHerpes simplex virus type 1/2 (HSV-1/-2), cytomegalovirus (CMV), and Epstein–Barr virus (EBV) correlate strongly with infections of the central nervous system. The objective of this study was to develop a method for the simultaneous detection of HSV-1/-2, CMV, and EBV DNA by the fluorescence polarization assay based on asymmetric polymerase chain reaction (PCR) and hybridization.MethodsDNA of HSV-1/-2, CMV, and EBV was amplified in an asymmetric PCR by a universal primer system. The amplicons were then detected by the fluorescence polarization assay. In this method, the probes for HSV-1/-2, CMV, and EBV hybridized with their respective target amplicons, and the hybridization resulted in an increase in the fluorescence polarization values. Infections of HSV-1/-2, CMV, and EBV were determined by the increased fluorescence polarization values. The DNA extracted from whole blood and cerebrospinal fluid samples was subjected to fluorescence polarization and a previously published multiplex PCR assay in parallel.ResultsCompared to the multiplex PCR assay, no significant difference in the numbers of samples positive for the human herpesviruses was identified by the fluorescence polarization assay.ConclusionsThe fluorescence polarization assay presented in this study is a reliable, convenient, and cost-effective diagnostic tool that allows the detection of the four major human herpesviruses

Fast Unbalanced Private Computing on (Labeled) Set Intersection with Cardinality

Private computation on (labeled) set intersection (PCSI/PCLSI) is a secure computation protocol that allows two parties to compute fine-grained functions on set intersection, including cardinality, cardinality-sum, secret shared intersection and arbitrary functions. Recently, some computationally efficient PCSI protocols have emerged, but a limitation on these protocols is the communication complexity, which scales (super)-linear with the size of the large set. This is of particular concern when performing PCSI in the unbalanced case, where one party is a constrained device with a small set, and the other is a service provider holding a large set. In this work, we first formalize a new ideal functionality called shared characteristic and its labeled variety called shared characteristic with labels, from which we propose the frameworks of PCSI/PCLSI protocols. By instantiating our frameworks, we obtain a series of efficient PCSI/PCLSI protocols, whose communication complexity is linear in the size of the small set, and logarithmic in the large set. We demonstrate the practicality of our protocols with implementations. Experiment results show that our protocols outperform previous ones and the larger difference between the sizes of two sets, the better our protocols perform. For input set sizes $2^{10}$ and $2^{22}$ with items of length $128$ bits, our PCSI requires only $4.62$MB of communication to compute the cardinality; $4.71$MB of communication to compute the cardinality-sum. Compared with the state-of-the-art PCSI proposed by Chen et al., there are $58 \times$ and $77 \times$ reductions in the communication cost of computing cardinality and cardinality-sum

Detection of HBV Genotypes of Tumor Tissues and Serum by A Fluorescence Polarization Assay in North-Western China's Hepatocellular Carcinoma Patients

<p>Abstract</p> <p>Background</p> <p>The understanding of the distribution of hepatitis B virus genotypes and the occult hepatitis B virus infection in hepatocellular carcinoma may shed light into the prevention and treatment of hepatocellular carcinoma. The purpose of the study is to investigate hepatitis B virus genotypes distribution, the high-risk genotypes and the occult infection in north-western China's hepatocellular carcinoma patients.</p> <p>Methods</p> <p>Hepatitis B virus genotypes A-D of hepatocellular carcinoma tumor tissues and serum samples in 268 north-western China hepatocellular carcinoma patients were detected by fluorescence polarization assay. The hepatitis B virus genotypes in serum and matched primary tumor tissue samples were compared. Hepatitis B surface antigen and α-fetoprotein in serum were detected. Occult hepatitis B virus infections were analyzed. The relationship between hepatitis B virus genotypes and clinicopathologic characteristics were analyzed statistically using SPSS v.10.0.</p> <p>Results</p> <p>Intrahepatic hepatitis B virus DNA was detected in 83.6% of 268 patients, whereas serum hepatitis B virus DNA was detected in 78.7%. The hepatitis B virus genotypes in serum were consistent with the results in matched tumor tissue. Intrahepatic hepatitis B virus genotype B and C were detected respectively in 11.6% and 54.5% of the patients. Mixed intrahepatic hepatitis B virus genotypes were detected in 13.4% of 268 patients. There was not mixed hepatitis B virus infection in Edmondonson grade I. The patients with mixed HBV genotypes exhibited statistically significant different Edmondson grade than the patients with single type HBV infection (p < 0.05). Hepatitis B surface antigens were positive in 77.2% of 268 patients. Hepatitis B virus genotype C was detected in 64.7% of occult infected patients. There was no significant differences of patients' ages and α-fetoprotein level in different groups of intrahepatic hepatitis B virus genotypes (p > 0.05).</p> <p>Conclusions</p> <p>Hepatitis B virus genotype C was associated closely with the development of hepatocellular carcinoma and the occult hepatitis B virus infection in patients in north-western China. There was a relatively high prevalence of mixed hepatitis B virus infection in Edmondonson grade III-IV.</p

Fabrication and properties of PLA/β-TCP scaffolds using liquid crystal display (LCD) photocuring 3D printing for bone tissue engineering

Introduction: Bone defects remain a thorny challenge that clinicians have to face. At present, scaffolds prepared by 3D printing are increasingly used in the field of bone tissue repair. Polylactic acid (PLA) has good thermoplasticity, processability, biocompatibility, and biodegradability, but the PLA is brittle and has poor osteogenic performance. Beta-tricalcium phosphate (β-TCP) has good mechanical properties and osteogenic induction properties, which can make up for the drawbacks of PLA.Methods: In this study, photocurable biodegradable polylactic acid (bio-PLA) was utilized as the raw material to prepare PLA/β-TCP slurries with varying β-TCP contents (β-TCP dosage at 0%, 10%, 20%, 30%, 35% of the PLA dosage, respectively). The PLA/β-TCP scaffolds were fabricated using liquid crystal display (LCD) light-curing 3D printing technology. The characterization of the scaffolds was assessed, and the biological activity of the scaffold with the optimal compressive strength was evaluated. The biocompatibility of the scaffold was assessed through CCK-8 assays, hemocompatibility assay and live-dead staining experiments. The osteogenic differentiation capacity of the scaffold on MC3T3-E1 cells was evaluated through alizarin red staining, alkaline phosphatase (ALP) detection, immunofluorescence experiments, and RT-qPCR assays.Results: The prepared scaffold possesses a three-dimensional network structure, and with an increase in the quantity of β-TCP, more β-TCP particles adhere to the scaffold surface. The compressive strength of PLA/β-TCP scaffolds exhibits a trend of initial increase followed by decrease with an increasing amount of β-TCP, reaching a maximum value of 52.1 MPa at a 10% β-TCP content. Degradation rate curve results indicate that with the passage of time, the degradation rate of the scaffold gradually increases, and the pH of the scaffold during degradation shows an alkaline tendency. Additionally, Live/dead staining and blood compatibility experiments suggest that the prepared PLA/β-TCP scaffold demonstrates excellent biocompatibility. CCK-8 experiments indicate that the PLA/β-TCP group promotes cell proliferation, and the prepared PLA/β-TCP scaffold exhibits a significant ability to enhance the osteogenic differentiation of MC3T3-E1 cells in vitro.Discussion: 3D printed LCD photocuring PLA/β-TCP scaffolds could improve surface bioactivity and lead to better osteogenesis, which may provide a unique strategy for developing bioactive implants in orthopedic applications

EINFLUSSE DES PRAGER PARLERKREISES AUF DIE ARCHITEKTONISCHE PLASTIK AUS ILOK

In elem maler ischen syrmischen Stacltchen I lok ani h o hen Ufer cler Donau, umgeben von mi t telalterlichen Mauern, steht clie trot z cler t u r k ischen Her rschaft ( 1 526.— 1688.) erhalten gebliebene Franziskanerkirche cles hl . Johann Kapistran. Diese Kirche, die f ruher ei n ancleres Patrozinium hat te, wurde einige Male umgebaut ,im 18. Jh. barockisiert, und Anfang cles 20 Jhs. neugotisch restauriert. Bei clieser Gelegenheit wurcle ihr architektonisch- plastischer Schmuck e n t fernt , c ler s i c ht s eit dem Jahr 1912. in Zagreb befindet ( jetzt im Hi stor ischen Museum) . ln der Ki rche verblieb cine Konsolemit cler Jahreszahl 1468., nach welcher vor e iner halben Jahrhundert J. Br unšmid auch die Ubrigen erhaltenen Konsolen in clie zweite Halfte des 15. Jhs. clatierte. De r S t i l e i n iger von ihnen spr icht j ecloch fur cine andere Entstehungszeit. Es werden anschliessend st i l istische Merkmale dreier clieser Denkmaler untersucht: einer Konsole mit Laubwerk (42x42x59 cm), einer Konsole mi t Teufelskopf (46x37x47 cm) und einer Konsole mit dem Kopfe eines Monstrums (29x48x48 cna), die alle aus Sanclstein gemeisselt sincI. Ein Vergleich mi t Ko nsolen in cler Kathedrale i n Prag, sowie auch nai t v erwancltem Mater ial i n Zagreb, Slowenien, Osterreich uncI i n Ungarn (Budapest), welches unter elena Einfluss c ler Werkstatt der Par ler i n Pr ag entstanden i s t , z e i gt , class auch clie Konsolen aus Ilok Zuge aufweisen, die fur elen von der prager Parlerwerkstatt gemeisselten architektonisch-plastischen Schmuck kennzeichnend sind. Es wircl vorausgesetzt, class cliese Einflusse nicht auf di rektem Wege von Prag nach I lok gelang sincI, sondern uber Buclapest. Dort haben — nach Gerevich — n ach elem Jahre 1385.,nachclem c!er Chor cler Katheclrale in Prag fer t iggestellt war , al tere Meister cler ersten Generation gearbeitet ( si e konnten etwa 60 Jahre alt gewesen sein). Diese Meister sincI wahrscheinlich auf j ener alteren St i lstufe stehengeblieben, die ihr e Werke f u r clie prager Katheclrale kennzeichnet, bevor sie in di e Wel t h i nausz ogen. Danti t k o nnt e ma n d i e archaischen Zuge der Konsolen aus Ilok erklaren, clie — b edingt durch clieubrigen Zustancle im Lancle — t rot z ihrer archaischen Zuge in clieser provinziellen Umgebung in c(er Zeit cles Ubergangs vom 14. ins 15. Jh. ent stanclen sein konnten. Als Vermi t t ler kamen Konig Sigisniuncl von Luxemburg uncI Nikola Gor janski i n Bet racht . Konig Sigismund war f i m J a hre 1394. elen Aufstancl Paližna\u27s uncI der Br uder Ho r vat n iecle, und I ehrte nach cler Schfacht bei Nikopolis im Jahre 1397. aus cler Gerangenschaft i n s ei n L anel zuruck. Nikola Gor janski, Sigismuncl\u27s treuer Anhanger, war Banus von Kroatien (1397.1401.), uncI sei t elem Jahr e 1402. der ma cht ige Palatin von Ungarn, elem unter v ielen ancleren Gutern auch I lok gehor te. Bis jetzt war Zagreb al s cler sgcllichste Punkt bekannt, l>is zu welchem clie Ein f lusse cler beruhnnten Werkstatt cler Parl in Prag reichten. Nach elem Dargelegten ware jetzt I lok i n suclostlicher Richtung cler entfernteste Punkt i n cler kunstlerischen Geographie Europas, bi s z u we l chem s ic h d i e Erfahrungen <lieser Werkstatt er st reckte

Systematic characterization of gene families and functional analysis of PvRAS3 and PvRAS4 involved in rosmarinic acid biosynthesis in Prunella vulgaris

Prunella vulgaris is an important material for Chinese medicines with rosmarinic acid (RA) as its index component. Based on the chromosome-level genome assembly we obtained recently, 51 RA biosynthesis-related genes were identified. Sequence feature, gene expression pattern and phylogenetic relationship analyses showed that 17 of them could be involved in RA biosynthesis. In vitro enzymatic assay showed that PvRAS3 catalyzed the condensation of p-coumaroyl-CoA and caffeoyl-CoA with pHPL and DHPL. Its affinity toward p-coumaroyl-CoA was higher than caffeoyl-CoA. PvRAS4 catalyzed the condensation of p-coumaroyl-CoA with pHPL and DHPL. Its affinity toward p-coumaroyl-CoA was lower than PvRAS3. UPLC and LC-MS/MS analyses showed the existence of RA, 4-coumaroyl-3’,4’-dihydroxyphenyllactic acid, 4-coumaroyl-4’-hydroxyphenyllactic acid and caffeoyl-4’-hydroxyphenyllactic acid in P. vulgaris. Generation and analysis of pvras3 homozygous mutants showed significant decrease of RA, 4-coumaroyl-3’,4’-dihydroxyphenyllactic acid, 4-coumaroyl-4’-hydroxyphenyllactic acid and caffeoyl-4’-hydroxyphenyllactic acid and significant increase of DHPL and pHPL. It suggests that PvRAS3 is the main enzyme catalyzing the condensation of acyl donors and acceptors during RA biosynthesis. The role of PvRAS4 appears minor. The results provide significant information for quality control of P. vulgaris medicinal materials