Purification on a Recombinant Nucleocapsid Protein of Newcastle Disease Virus Using Expanded Bed Adsorption Chromatography

The purification of histidine-tagged nucleocapsid protein (NP) of Newcastle disease virus (NDV) in expanded bed adsorption (EBA) directly from unclarified Escherichia coli feedstock was investigated. Streamline 925 Column (ID = 25 mm) was used as a contactor and Streamline chelating immobilised with ~ i "ion was used as affinity adsorbent. Unclarified E. coli feedstock of 8% biomass wet mass (w/v) was loaded onto the stable expanded bed. The adsorption properties of the Streamline chelating were investigated by batch adsorption. The adsorption of NP protein onto the Streamline chelating was observed to follow the Langmuir isotherm. Optimal binding and elution conditions for the application of EBA were developed. Batch binding experiments results showed that the optimal pH for adsorption and elution buffer is 8.0. Elution buffer which contained 50 mM imidazole was used to remove the unbound proteins and elution buffer with 350 mM imidazole was used to elute NP protein from the adsorbent. Elution in packed bed column showed that the highest NP protein yield was achieved at a flow velocity of 10 crn/h. The bed expansion characteristics of the Streamline chelating with buffer and unclarified feedstock were determined by visually monitoring the bed height as a function of increasing superficial velocity. The dynamic binding capacity of the adsorbent for NP protein was determined in the expanded bed column to be 2.9 mg/mL adsorbent. These results were used to develop a large scale purification of NP protein in Streamline 25 Column. Xi< performance of a conventional purification methodj racked bed adsorption (PBA) and EBA for the purification of the NP protein from E. coli feedstock was assessed and compared. The conventional way for the recovery of NP proteins involved multiple steps such as centrifugation, precipitation, dialysis and sucrose gradient ultracentrifugation. For the PBA, feedstock clarified by centrifuge was used for column loading, while in EBA; unclarified feedstock was used. The final protein yield obtained in conventional and PBA methods was 1.3% and 5.6% respectively. It was demonstrated that the EBA achieved the highest final protein yield of 9.6% with a purification factor of 6.6. In addition, the total processing time was reduced from 56 h to 7.5 h for EBA compared to that of the conventional method. Within the range of the experimental works, result from this study suggested that EBA technique allowed clarification, concentration and initial purification to be combined into a single step operation. The expanded bed purification for NP protein was efficient and scalable, promising its implementation in the large scale production of protein

Style Transfer in Text: Exploration and Evaluation

Style transfer is an important problem in natural language processing (NLP). However, the progress in language style transfer is lagged behind other domains, such as computer vision, mainly because of the lack of parallel data and principle evaluation metrics. In this paper, we propose to learn style transfer with non-parallel data. We explore two models to achieve this goal, and the key idea behind the proposed models is to learn separate content representations and style representations using adversarial networks. We also propose novel evaluation metrics which measure two aspects of style transfer: transfer strength and content preservation. We access our models and the evaluation metrics on two tasks: paper-news title transfer, and positive-negative review transfer. Results show that the proposed content preservation metric is highly correlate to human judgments, and the proposed models are able to generate sentences with higher style transfer strength and similar content preservation score comparing to auto-encoder.Comment: To appear in AAAI-1

Recovery of histidine-tagged nucleocapsid protein of Newcastle disease virus using immobilised metal affinity chromatography

An immobilised metal affinity packed bed adsorption chromatography (IMA-PBAC) for the purification of recombinant nucleocapsid protein (NP) of Newcastle disease virus (NDV) directly from clarified feedstock was developed. The XK 16/20 (i.d. = 16 mm) was used as a packed bed column and Streamline chelating adsorbent immobilised with Ni2+ ion was used as IMA adsorbent. This purification method has resulted in a 59% adsorption and 5.6% recovery of NP protein. Adsorbed NP proteins were successfully recovered using a two-step elution protocol which employed elution buffer 1 containing 50 mM imidazole to eliminate contaminating proteins and elution buffer 2 containing 350 mM imidazole to recover the NP protein at pH 8 with flow velocity of 10 cm h−1. About 70% of the adsorbed NP protein was eluted. The purity of the recovered NP protein was about 70% and the volume of processing fluid was reduced by a factor of 4. The antigenic features of purified NP proteins were confirmed by enzyme-linked immunosorbent assay (ELISA) analysis

Purification of recombinant nucleocapsid protein of Newcastle disease virus from unclarified feedstock using expanded bed adsorption chromatography

In the present work, a single-step purification of recombinant nucleocapsid protein (NP) of the Newcastle disease virus (NDV) directly from unclarified feedstock using an expanded bed adsorption chromatography (EBAC) was developed. Streamline 25 column (ID = 25 mm) was used as a contactor and Streamline chelating adsorbent immobilized with Ni2+ ion was used as affinity adsorbent. The dynamic binding capacity of Ni2+-loaded Streamline chelating adsorbent for the NP protein in unclarified feedstock was found to be 2.94 mg ml−1 adsorbent at a superficial velocity of 200 cm h−1. The direct purification of NP protein from unclarified feedstock using expanded bed adsorption has resulted in a 31% adsorption and 9.6% recovery of NP protein. The purity of the NP protein recovered was about 70% and the volume of processing fluid was reduced by a factor of 10. The results of the present study show that the IMA-EBAC developed could be used to combine the clarification, concentration and initial purification steps into a single-step operation

SymmeGuess: Fun beyond Symmetry Learning

Computer application can be used for artistic design and as a means to facilitate the understanding of mathematical concepts. This paper presents a game-based application as a visual learning tool for mathematics and art subjects. The objectives of this application are to enable learners to build their knowledge on symmetry and to explore the beauty of symmetrical patterns with confidence and enjoyment