Medium optimization for endochitinase production by recombinant Pichia pastoris ZJGSU02 using response surface methodology

Plackett-Burman design and response surface methodology were employed to optimize the medium components for endochitinase production by Pichia pastoris. A Plackett- Burman design of seven factors with 12 runs was applied to evaluate the effects of different medium components. Yeast extract, oleic acid and Tween-80 were found to have significant influence on endochitinase production. The optimal concentrations of three factors were investigated by the response surface methodology using Box- Behnken design. The optimal medium components obtained for achieving the maximum activity of the endochitinase were as follows: Yeast extract 24.36 g/l, tryptone 20 g/l, YNB 5.0 g/l, potassium phosphate 100 mM, methanol 5 ml/l, oleic acid 1.758 ml/l, Tween-80 6.2 ml/l, Pichia trace metals (PTM1) 4.0 ml/ l and biotin 4.00 × 10-4 g/l. Under these conditions, endochitinase activity was up to 88.26 μ/ml, which was about 1.14-fold higher than using the original medium (77.62 μ/ml). This work will be very helpful for large-scale production of endochitinase for future industrial application.Keywords: Recombinant endochitinase, Plackett-Burman design, response surface methodology, fermentatio

Attenuation of transcriptional bursting in mRNA transport

Due to the stochastic nature of biochemical processes, the copy number of any given type of molecule inside a living cell often exhibits large temporal fluctuations. Here, we develop analytic methods to investigate how the noise arising from a bursting input is reshaped by a transport reaction which is either linear or of the Michaelis-Menten type. A slow transport rate smoothes out fluctuations at the output end and minimizes the impact of bursting on the downstream cellular activities. In the context of gene expression in eukaryotic cells, our results indicate that transcriptional bursting can be substantially attenuated by the transport of mRNA from nucleus to cytoplasm. Saturation of the transport mediators or nuclear pores contributes further to the noise reduction. We suggest that the mRNA transport should be taken into account in the interpretation of relevant experimental data on transcriptional bursting.Comment: 18 pages, 3 figure

De novo assembly and characterization of transcriptome using Illumina paired-end sequencing and identification of CesA gene in ramie (Boehmeria nivea L. Gaud)

BACKGROUND: Ramie fiber, extracted from vegetative organ stem bast, is one of the most important natural fibers. Understanding the molecular mechanisms of the vegetative growth of the ramie and the formation and development of bast fiber is essential for improving the yield and quality of the ramie fiber. However, only 418 expressed tag sequences (ESTs) of ramie deposited in public databases are far from sufficient to understand the molecular mechanisms. Thus, high-throughput transcriptome sequencing is essential to generate enormous ramie transcript sequences for the purpose of gene discovery, especially genes such as the cellulose synthase (CesA) gene. RESULTS: Using Illumina paired-end sequencing, about 53 million sequencing reads were generated. De novo assembly yielded 43,990 unigenes with an average length of 824 bp. By sequence similarity searching for known proteins, a total of 34,192 (77.7%) genes were annotated for their function. Out of these annotated unigenes, 16,050 and 13,042 unigenes were assigned to gene ontology and clusters of orthologous group, respectively. Searching against the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG) indicated that 19,846 unigenes were mapped to 126 KEGG pathways, and 565 genes were assigned to http://starch and sucrose metabolic pathway which was related with cellulose biosynthesis. Additionally, 51 CesA genes involved in cellulose biosynthesis were identified. Analysis of tissue-specific expression pattern of the 51 CesA genes revealed that there were 36 genes with a relatively high expression levels in the stem bark, which suggests that they are most likely responsible for the biosynthesis of bast fiber. CONCLUSION: To the best of our knowledge, this study is the first to characterize the ramie transcriptome and the substantial amount of transcripts obtained will accelerate the understanding of the ramie vegetative growth and development mechanism. Moreover, discovery of the 36 CesA genes with relatively high expression levels in the stem bark will present an opportunity to understand the ramie bast fiber formation and development mechanisms

Systematical research on the aerodynamic noise of the high-lift airfoil based on FW-H method

In numerical computation of aerodynamic noises, the solution accuracy of flow fields has an obvious impact on detailed computation of eddy turbulence and acoustic results. In this paper, LES (Large Eddy Simulation) was used to conduct numerical simulation of flow fields of three-dimensional high-lift L1T2 airfoil. Unsteady flow field data on the solid wall face was extracted as the noise source. The integration method FW-H (Ffowcs Williams-Hawkings) was used to compute far-field noises. The numerical computation method was verified by experiments. Results show that: the numerical computation method used in this paper can provide an accurate solution for computing far-field aerodynamic noises. Finally, based on the verified numerical model, contribution amounts made by each high-lift airfoil component to noises as well as major factors affecting aerodynamic noises were analyzed. Computational results show that: the leading edge slats generated aerodynamic noises mainly because of the unsteady waves which were caused by the grooves between the slat and main wing, as well as small wake eddies generated on the trailing edge of slats; flaps generated aerodynamic noises mainly because of mixing between high-frequency small-scale eddies and low-frequency large-scale eddies caused by flow separation around the wing flaps. Acoustic directivity of leading edge slats and trailing edge flaps showed an obvious dipole characteristic. For both of them, the sound pressure levels reached the maximum value in the direction perpendicular to the chord line

Eficácia da intervenção de enfermagem para aumento da esperança em pacientes com câncer: uma meta-análise

Objetivo: meta-análise para avaliar a eficácia da intervenção de enfermagem, no nível de esperança para pacientes com câncer. Método: foram pesquisados bancos de dados eletrônicos. Dois dos autores, de forma independente, extraíram os dados dos estudos elegíveis e os agruparam no software Stata 13.0. Resultado: nove ensaios clínicos randomizados foram incluídos e a qualidade metodológica destes estudos foi avaliada utilizando as recomendações do manual Cochrane. Um modelo de efeito aleatório foi usado para combinar resultados dos estudos elencados. O agrupamento dos resultados por meio de um modelo de efeitos fixos mostrou primeiros escores revelaram um efeito significativamente maior após o uso da intervenção de enfermagem entre os grupos. Foi identificada heterogeneidade entre os estudos para pós-teste (df = 8, p = 0.000; I2 =76.1 %). Os resultados indicaram heterogeneidade significativa nos nove estudos selecionados. O teste para heterogeneidade não demonstrou homogeneidade entre os estudos de acompanhamento (df = 8, p = 0.328; I2 = 12.9 %), mas sem significância estatística. Conclusão: as evidências atuais sugerem que a intervenção de enfermagem tem um efeito positivo no sentimento de esperança em pacientes com câncer. No entanto, são necessários mais ensaios controlados randomizados em maior escala e de alta qualidade para confirmar esses resultados.Objetivo: evaluar la eficacia de la intervención de enfermería para pacientes oncológicos en el nivel de esperanza en un meta análisis. Método: se buscó información en bases de datos electrónicas. Dos de los autores extrajeron de forma independiente los datos de los estudios de elegibilidad, y se utilizó el software Stata 13.0 para agrupar los datos. Resultados: se incluyeron nueve ensayos aleatorios controlados y se evaluó la calidad metodológica del ensayo controlado aleatorizado (ECA) utilizando las recomendaciones del manual Cochrane. Se utilizó un modelo de efectos aleatorios para combinar los resultados de los estudios elegibles. Los resultados agrupados utilizando el modelo de efectos fijos mostraron que las puntuaciones al primer efecto aumentan significativamente después del uso de la intervención de enfermería entre los grupos. Se observó heterogeneidad entre los estudios de post-prueba (df = 8, P = 0.000; I2 =76.1 %). Los resultados indicaron heterogeneidad significativa en los nueve estudios seleccionados. La prueba de heterogeneidad no mostró homogeneidad entre los estudios de seguimiento (df = 8, P = 0.328; I2 = 12.9 %), pero no hay significación estadística. Conclusión: la evidencia actual sugiere que la intervención de enfermería tiene un efecto positivo en la esperanza en pacientes con cáncer. Sin embargo, se necesitan más ensayos controlados aleatorios de gran escala y de alta calidad para confirmar estos resultados.Objective: to evaluate the efficacy of nursing interventions to increase the level of hope in cancer patients, in a meta-analysis. Methods: electronic databases were searched. Two of the authors independently extracted data from the eligible studies, and Stata 13.0 software was used to pool the data. Results: nine randomized controlled trials were included, and methodological quality of each randomized controlled trial (RCT) was evaluated using Cochrane handbook recommendations. A random effects model was used to combine results from eligible studies. The pooled results using the fixed effects model showed that scores to first effects increase significantly after the use of nursing intervention between the groups. Heterogeneity was observed among the studies for posttest (df = 8, P = 0.000; I2 =76.1 %). The results indicated significant heterogeneity across the nine selected studies. The test for heterogeneity showed no homogeneity among studies for follow-up (df = 8, P = 0.328; I2 = 12.9 %), and there was no statistical significance. Conclusion: the current evidence suggests that nursing intervention has a positive effect on hope in cancer patients. However, more large-scale and high-quality randomized controlled trials are needed to confirm these results