Thermoactive cellulase-free xylanase production from alkaliphilic Bacillus strains using various agro-residues and their potential in biobleaching of kraft pulp

The four bacterial strains were isolated on media containing xylan and screened for xylanase activity. The bacterial strains (Ag12, Ag13, Ag20 and Ag32) were characterized based on morphological, biochemical and physiological characters and identified as belonging to the genus Bacillus. The effects of different factors such as pH (7.0 – 10.0), temperature (25.0 – 50.0°C) and inexpensive agro-residues (wheat straw, wheat bran and corncob) on xylanase production of strains were studied under shakeflask conditions. Maximal enzyme activities were obtained by cultivation in birch-wood xylan, but high enzyme production was also obtained on wheat straw and corncob when cultivated at pH 8.5. Under optimized fermentation conditions, no cellulolytic activity were detected on the crude extracts. Theeffects of temperature (40.0 – 80.0°C), pH (6.0 – 10.0) and salt concentration (1.0, 5.0 and 10.0%) on the xylanases activity were determined. The maximum activity was obtained temperature 60.0°C and pH at 9.0. The enzyme was stable at 60.0°C for more than 60 min, suggesting that the xylanases of Bacillus strains are thermoactive and being of interests for biobleaching processes. The effectiveness of crudexylanases from the strains Ag12, Ag20 and Ag32 on kraft pulp were carried out at pH 9.0 at 60.0°C. Biobleaching studies of kraft pulp with xylanases and its subsequent treatment with 1.0% EDTA (30 min at 50.0°C) and peroxide (80 min at 70.0°C), showed that the enzymes reduced the kappa number by 27.4, 61.7 and 75.3% and enhanced the brightness by 1.0, 1.5 and 3.0% from xylanases produced by strains Ag12, Ag20 and Ag32, respectively. These results suggest that the application of this xylanases to the paper and pulp industry may be very promising

Growth and reproduction studies on gilthead seabream (Sparus aurata) in Beymelek Lagoon, Turkey

In the present study, age, growth, length-weight relationship and reproduction were investigated in gilthead seabream (Sparus aurata L., 1758) collected from Beymelek Lagoon (Antalya, Turkey) between February 2006 and July 2007. The age, total length and weight of samples ranged from 0+ to 4 years, 10.6 to 35.5cm, and 18 to 928g, respectively. Growth was described by the standard form of the von Bertalanffy growth equation and the estimated parameters were L∞ = 44.6cm, k = 0.394yr^-1 and t0 = -1.331yr. Length-weight relationship was determined as W=0.0174TL^2.9769 (R^2=0.965), and weight increased with size isometrically (b = 2.9769) for all fish. Sex inversion occurred mainly at 26 cm in total length and females reached sexual maturity at 28.5 cm. The spawning period was from December to February, while the gamete emission peaked in December

Laser frequency stabilization to a single ion

A fundamental limit to the stability of a single-ion optical frequency standard is set by quantum noise in the measurement of the internal state of the ion. We discuss how the interrogation sequence and the processing of the atomic resonance signal can be optimized in order to obtain the highest possible stability under realistic experimental conditions. A servo algorithm is presented that stabilizes a laser frequency to the single-ion signal and that eliminates errors due to laser frequency drift. Numerical simulations of the servo characteristics are compared to experimental data from a frequency comparison of two single-ion standards based on a transition at 688 THz in 171Yb+. Experimentally, an instability sigma_y(100 s)=9*10^{-16} is obtained in the frequency difference between both standards.Comment: 15 pages, 5 figures, submitted to J. Phys.

Precision spectroscopy with two correlated atoms

We discuss techniques that allow for long coherence times in laser spectroscopy experiments with two trapped ions. We show that for this purpose not only entangled ions prepared in decoherence-free subspaces can be used but also a pair of ions that are not entangled but subject to the same kind of phase noise. We apply this technique to a measurement of the electric quadrupole moment of the 3d D5/2 state of 40Ca+ and to a measurement of the linewidth of an ultrastable laser exciting a pair of 40Ca+ ions

'Designer atoms' for quantum metrology

Entanglement is recognized as a key resource for quantum computation and quantum cryptography. For quantum metrology, the use of entangled states has been discussed and demonstrated as a means of improving the signal-to-noise ratio. In addition, entangled states have been used in experiments for efficient quantum state detection and for the measurement of scattering lengths. In quantum information processing, manipulation of individual quantum bits allows for the tailored design of specific states that are insensitive to the detrimental influences of an environment. Such 'decoherence-free subspaces' protect quantum information and yield significantly enhanced coherence times. Here we use a decoherence-free subspace with specifically designed entangled states to demonstrate precision spectroscopy of a pair of trapped Ca+ ions; we obtain the electric quadrupole moment, which is of use for frequency standard applications. We find that entangled states are not only useful for enhancing the signal-to-noise ratio in frequency measurements - a suitably designed pair of atoms also allows clock measurements in the presence of strong technical noise. Our technique makes explicit use of non-locality as an entanglement property and provides an approach for 'designed' quantum metrology

Quantum control, quantum information processing, and quantum-limited metrology with trapped ions

We briefly discuss recent experiments on quantum information processing using trapped ions at NIST. A central theme of this work has been to increase our capabilities in terms of quantum computing protocols, but we have also applied the same concepts to improved metrology, particularly in the area of frequency standards and atomic clocks. Such work may eventually shed light on more fundamental issues, such as the quantum measurement problem.Comment: Proceedings of the International Conference on Laser Spectroscopy (ICOLS), 10 pages, 5 figure

Testing the stability of fundamental constants with the 199Hg+ single-ion optical clock

Over a two-year duration, we have compared the frequency of the 199Hg+ 5d106s 2S 1/2 (F=0) 5d9 6s2 2D 5/2 (F=2) electric-quadrupole transition at 282 nm with the frequency of the ground-state hyperfine splitting in neutral 133Cs. These measurements show that any fractional time variation of the ratio nu(Cs)/nu(Hg) between the two frequencies is smaller than +/- 7 10^-15 / yr (1 sigma uncertainty). According to recent atomic structure calculations, this sets an upper limit to a possible fractional time variation of g(Cs) m_e / m_p alpha^6.0 at the same level.Comment: 4 pages with 3 figures. RevTeX 4, Submitted to Phys. Rev. Let

Squeezing of Atoms in a Pulsed Optical Lattice

We study the process of squeezing of an ensemble of cold atoms in a pulsed optical lattice. The problem is treated both classically and quantum-mechanically under various thermal conditions. We show that a dramatic compression of the atomic density near the minima of the optical potential can be achieved with a proper pulsing of the lattice. Several strategies leading to the enhanced atomic squeezing are suggested, compared and optimized.Comment: Latex, 9 pages, 10 figures, submitted to PR

Transferability of PCR-based diagnostic protocols: An international collaborative case study assessing protocols targeting the quarantine pine pathogen Fusarium circinatum

[EN] Fusarium circinatum is a harmful pathogenic fungus mostly attacking Pinus species and also Pseudotsuga menziesii, causing cankers in trees of all ages, damping-off in seedlings, and mortality in cuttings and mother plants for clonal production. This fungus is listed as a quarantine pest in several parts of the world and the trade of potentially contaminated pine material such as cuttings, seedlings or seeds is restricted in order to prevent its spread to disease-free areas. Inspection of plant material often relies on DNA testing and several conventional or real-time PCR based tests targeting F. circinatum are available in the literature. In this work, an international collaborative study joined 23 partners to assess the transferability and the performance of nine molecular protocols, using a wide panel of DNA from 71 representative strains of F. circinatum and related Fusarium species. Diagnostic sensitivity, specificity and accuracy of the nine protocols all reached values >80%, and the diagnostic specificity was the only parameter differing significantly between protocols. The rates of false positives and of false negatives were computed and only the false positive rates differed significantly, ranging from 3.0% to 17.3%. The difference between protocols for some of the performance values were mainly due to cross-reactions with DNA from non-target species, which were either not tested or documented in the original articles. Considering that participating laboratories were free to use their own reagents and equipment, this study demonstrated that the diagnostic protocols for F. circinatum were not easily transferable to end-users. More generally, our results suggest that the use of protocols using conventional or real-time PCR outside their initial development and validation conditions should require careful characterization of the performance data prior to use under modified conditions (i.e. reagents and equipment). Suggestions to improve the transfer are proposed.This work was supported by COST action FP1406 Pinestrength . The work of the Estonian team was supported by the Estonian Science Foundation grants PSG136 and IUT21-04. The work of Portuguese team from INIAV was financed by INIAV I.P. Institute. The work at U. Aveiro (Portugal) was financed by European Funds through COMPETE and National Funds through the Portuguese Foundation for Science and Technology (FCT) to CESAM (UID/AMB/50017/2013 POCI-01- 0145-FEDER-007638). The work of Slovenian team was financed through Slovenian Research Agency (P4-0107) and by the Slovenian Ministry of Agriculture, Forestry and Food (Public Forestry Service). The British work was financially supported by the Forestry Commission, UK. The French work was financially supported by the French Agency for Food, environmental and occupational health safety (ANSES). The work in New Zealand was funded by Operational Research Programmes, Ministry for Primary Industries, New Zealand.Ioos, R.; Aloi, F.; Piskur, B.; Guinet, C.; Mullett, M.; Berbegal Martinez, M.; Bragança, H.... (2019). Transferability of PCR-based diagnostic protocols: An international collaborative case study assessing protocols targeting the quarantine pine pathogen Fusarium circinatum. Scientific Reports. 9:1-17. https://doi.org/10.1038/s41598-019-44672-8S1179Schmale, D. G. III & Gordon, T. R. Variation in susceptibility to pitch canker disease, caused by Fusarium circinatum, in native stands of Pinus muricata. Plant Pathol. 52, 720–725 (2003).Gordon, T. R., Kirkpatrick, S. C., Aegerter, B. J., Wood, D. L. & Storer, A. J. Susceptibility of Douglas fir (Pseudotsuga menziesii) to pitch canker, caused by Gibberella circinata (anamorph = Fusarium circinatum). Plant Pathol. 55, 231–237 (2006).Martínez‐Álvarez, P., Pando, V. & Diez, J. J. Alternative species to replace Monterey pine plantations affected by pitch canker caused by Fusarium circinatum in northern Spain. Plant Pathol. 63, 1086–1094, https://doi.org/10.1111/ppa.12187 (2014).Wingfield, M. J. et al. Pitch canker caused by Fusarium circinatum - a growing threat to pine plantations and forests worldwide. Australas. Plant Path. 37, 319–334 (2008).Bezos, D., Martinez-Alvarez, P., Fernandez, M. & Diez, J. J. Epidemiology and management of pine pitch canker disease in Europe - a review. Balt. For. 23, 279–293 (2017).Landeras, E. et al. Outbreak of pitch canker caused by Fusarium circinatum on Pinus spp. in Northern Spain. Plant Dis. 89, 1015 (2005).Bragança, H., Diogo, E., Moniz, F. & Amaro, P. First report of pitch canker on pines caused by Fusarium circinatum in Portugal. Plant Dis. 93, 1079–1079, https://doi.org/10.1094/PDIS-93-10-1079A (2009).EFSA. Risk assessment of Gibberella circinata for the EU territory and identification and evaluation of risk management options. EFSA Journal 8, 1620 (2010).Carlucci, A., Colatruglio, L. & Frisullo, S. First report of pitch canker caused by Fusarium circinatum on Pinus halepensis and P. pinea in Apulia (Southern Italy). Plant Dis. 91, 1683 (2007).Vettraino, A., Potting, R. & Raposo, R. EU legislation on forest plant health: an overview with a focus on Fusarium circinatum. Forests 9, 568 (2018).Möykkynen, T., Capretti, P. & Pukkala, T. Modelling the potential spread of Fusarium circinatum, the causal agent of pitch canker in Europe. Annals of Forest Sciences 72, 169–181 (2015).Bustin, S. A. et al. The MIQE guidelines: minimum information for publication of quantitative real-time PCR experiments. Clin Chem 55, https://doi.org/10.1373/clinchem.2008.112797 (2009).EPPO. PM 7/91(1): Gibberella circinata. EPPO Bull. 39, 298–309 (2009).ISTA. 7-009: Detection of Gibberella circinata on Pinus spp. (pine) and Pseudotsuga menziesii (Douglas-fir) seed. Validated Seed Health Testing Methods (2015).IPPC. ISPM 27, Diagnostic protocols for regulated pests, DP 22: Fusarium circinatum (2017).EPPO. PM 7/98 (2) Specific requirements for laboratories preparing accreditation for a plant pest diagnostic activity. EPPO Bull. 44, 117–147, https://doi.org/10.1111/epp.12118 (2014).Nirenberg, H. I. & O’Donnell, K. New Fusarium species and combinations within the Gibberella fujikuroi species complex. Mycologia 90, 434–458 (1998).Britz, H., Coutinho, T. A., Wingfield, M. J. & Marasas, W. F. O. Validation of the description of Gibberella circinata and morphological differentiation of the anamorph Fusarium circinatum. Sydowia 54, 9–22 (2002).Mullett, M., Pérez-Sierra, A., Armengol, J. & Berbegal, M. Phenotypical and molecular characterisation of Fusarium circinatum: correlation with virulence and fungicide sensitivity. Forests 8, 458 (2017).Herron, D. A. et al. Novel taxa in the Fusarium fujikuroi species complex from Pinus spp. Stud. Mycol. 80, 131–150, https://doi.org/10.1016/j.simyco.2014.12.001 (2015).Storer, G. & Clark, S. L. Association of the pitch canker fungus, Fusarium subglutinans f.sp. pini, with Monterey pine seeds and seedlings in California. Plant Pathol. 47, 649–656, https://doi.org/10.1046/j.1365-3059.1998.00288.x (1998).Schweigkofler, W., O’Donnell, K. & Garbelotto, M. Detection and quantification of airborne conidia of Fusarium circinatum, the causal agent of pine pitch canker, from two California sites by using a real-time PCR approach combined with a simple spore trapping method. Appl. Environ. Microbiol. 70, 3512–3520 (2004).Ramsfield, T. D., Dobbie, K., Dick, M. A. & Ball, R. D. Polymerase chain reaction-based detection of Fusarium circinatum, the causal agent of pitch canker disease. Molecular Ecology Resources 8, 1270–1273 (2008).Ioos, R., Fourrier, C., Iancu, G. & Gordon, T. R. Sensitive Detection of Fusarium circinatum in Pine Seed by Combining an Enrichment Procedure with a Real-Time Polymerase Chain Reaction Using Dual-Labeled Probe Chemistry. Phytopathology 99, 582–590, https://doi.org/10.1094/PHYTO-99-5-0582 (2009).Dreaden, T. J., Smith, J. A., Barnard, E. L. & Blakeslee, G. Development and evaluation of a real-time PCR seed lot screening method for Fusarium circinatum, causal agent of pitch canker disease. For. Path. 42, 405–411, https://doi.org/10.1111/j.1439-0329.2012.00774.x (2012).Fourie, G. et al. Culture-independent detection and quantification of Fusarium circinatum in a pine-producing seedling nursery. Southern Forests: a Journal of Forest Science 76, 137–143, https://doi.org/10.2989/20702620.2014.899058 (2014).Lamarche, J. et al. Molecular detection of 10 of the most unwanted alien forest pathogens in Canada using Real-Time PCR. PLoS ONE 10, e0134265, https://doi.org/10.1371/journal.pone.0134265 (2015).Luchi, N., Pepori, A. L., Bartolini, P., Ioos, R. & Santini, A. Duplex real-time PCR assay for the simultaneous detection of Caliciopsis pinea and Fusarium circinatum in pine samples. Applied Microbiology and Biotechnology 102, 7135–7146, https://doi.org/10.1007/s00253-018-9184-1 (2018).Sandoval-Denis, M., Swart, W. J. & Crous, P. W. New Fusarium species from the Kruger National Park, South Africa. MycoKeys 34, https://doi.org/10.3897/mycokeys.34.25974 (2018).Steenkamp, E. T., Wingfield, B. D., Desjardins, A. E., Marasas, W. F. & Wingfield, M. J. Cryptic speciation in Fusarium subglutinans. Mycologia 94, 1032–1043 (2002).Garcia-Benitez, C. et al. Proficiency of real-time PCR detection of latent Monilinia spp. infection in nectarine flowers and fruit. Phytopathologia Mediterranea 56, 242–250 (2017).Ebentier, D. L. et al. Evaluation of the repeatability and reproducibility of a suite of qPCR-based microbial source tracking methods. Water Research 47, 6839–6848, https://doi.org/10.1016/j.watres.2013.01.060 (2013).Bustin, S. & Huggett, J. qPCR primer design revisited. Biomolecular Detection and Quantification 14, 19–28, https://doi.org/10.1016/j.bdq.2017.11.001 (2017).Grosdidier, M., Aguayo, J., Marçais, B. & Ioos, R. Detection of plant pathogens using real-time PCR: how reliable are late Ct values? Plant Pathol. 66, 359–367, https://doi.org/10.1111/ppa.12591 (2017).Al-Soud, W. A. & Rådström, P. Capacity of nine thermostable DNA polymerases to mediate DNA amplification in the presence of PCR-inhibiting samples. Applied and environmental microbiology 64, 3748–3753 (1998).Saunders, G. C., Dukes, J., Parkes, H. C. & Cornett, J. H. Interlaboratory study on thermal cycler performance in controlled PCR and random amplified polymorphic DNA analyses. Clinical chemistry 47, 47–55 (2001).Boutigny, A.-L. et al. Optimization of a real-time PCR assay for the detection of the quarantine pathogen Melampsora medusae f. sp. deltoidae. Fungal Biology 117, 389–398, https://doi.org/10.1016/j.funbio.2013.04.001 (2013).Guinet, C., Fourrier-Jeandel, C., Cerf-Wendling, I. & Ioos, R. One-step detection of Monilinia fructicola, M. fructigena, and M. laxa on Prunus and Malus by a multiplex real-time PCR assay. Plant Dis. 100, 2465–2474, https://doi.org/10.1094/PDIS-05-16-0655-RE (2016).Aguayo, J. et al. Development of a hydrolysis probe-based real-time assay for the detection of tropical strains of Fusarium oxysporum f. sp. cubense race 4. PLoS ONE 12, e0171767, https://doi.org/10.1371/journal.pone.0171767 (2017).Broeders, S. et al. Guidelines for validation of qualitative real-time PCR methods. Trends in Food Science & Technology 37, 115–126, https://doi.org/10.1016/j.tifs.2014.03.008 (2014).Pelloux, H. et al. A second European collaborative study on polymerase chain reaction for Toxoplasma gondii, involving 15 teams. FEMS Microbiology Letters 165, 231–237, https://doi.org/10.1111/j.1574-6968.1998.tb13151.x (1998).Leslie, J. F. & Summerell, B. A. The Fusarium laboratory manual. (Blackwell Publishing, 2006).Ioos, R. et al. Test performance study of diagnostic procedures for identification and detection of Gibberella circinata in pine seeds in the framework of a EUPHRESCO project. EPPO Bull. 43, 267–275, https://doi.org/10.1111/epp.12037 (2013).Geiser, D. M. FUSARIUM-ID v. 1.0: a DNA sequence database for identifying Fusarium. Eur. J. Plant Pathol. 110, 473–479 (2004).White, T. J., Bruns, T., Lee, S. & Taylor, J. In PCR protocols: a guide to method and applications (eds Gelfand, D. H., Innis M. A., Sninsky, J. J. and White, T. J.) 315–322 (Academic Press, 1990).Nirenberg, H. I. A simplified method for identifying Fusarium spp. occurring on wheat. Canadian Journal of Botany 59, 1599–1609 (1981).Chabirand, A., Loiseau, M., Renaudin, I. & Poliakoff, F. Data processing of qualitative results from an interlaboratory comparison for the detection of “Flavescence dorée” phytoplasma: How the use of statistics can improve the reliability of the method validation process in plant pathology. PLoS ONE 12, e0175247, https://doi.org/10.1371/journal.pone.0175247 (2017).Loreti, S. et al. Performance of diagnostic tests for the detection and identification of Pseudomonas syringae pv. actinidiae (Psa) from woody samples. European Journal of Plant Pathology, https://doi.org/10.1007/s10658-018-1509-5 (2018).International Standardization Organization. ISO 16140:2003 Microbiology of food and animal feeding stuffs - Protocol for the validation of alternative methods (2003).Langton, S., Chevennement, R., Nagelkerke, N. & Lombard, B. Analysing collaborative trials for qualitative microbiological methods: accordance and concordance. International Journal of Food Microbiology 79, 175–181 (2002).R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna (2014). R Foundation for Statistical Computing (2017).Wickham, H. ggplot2 : elegant graphics for data analysis. (Springer, 2016)