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Current industry practices for large-scale mammalian cell cultures typically employ a standard platform fed-batch process with fixed volume bolus feeding. Although widely used, these processes are unable to respond to actual nutrient consumption demands from the culture, which can result in accumulation of by-products and depletion of certain nutrients. This work demonstrates the application of a fully automated cell culture control, monitoring, and data processing system to achieve significant productivity improvement via dynamic feeding and media optimization. Two distinct feeding algorithms were used to dynamically alter feed rates. The first method is based upon on-line capacitance measurements where cultures were fed based on growth and nutrient consumption rates estimated from integrated capacitance. The second method is based upon automated glucose measurements obtained from the Nova Bioprofile FLEX® autosampler where cultures were fed to maintain a target glucose level which in turn maintained other nutrients based on a stoichiometric ratio. All of the calculations were done automatically through in-house integration with a Delta V process control system. Through both media and feed strategy optimization, a titer increase from the original platform titer of 5 to 6.3 g/L was achieved for cell line A, and a substantial titer increase of 4 to over 9 g/L was achieved for cell line B with comparable product quality. Glucose was found to be the best feed indicator, but not all cell lines benefited from dynamic feeding and optimized feed media was critical to process improvement. Our work demonstrated that dynamic feeding has the ability to automatically adjust feed rates according to culture behavior, and that the advantage can be best realized during early and rapid process development stages where different cell lines or large changes in culture conditions might lead to dramatically different nutrient demands. Biotechnol. Bioeng. 2013; 110: 191-205. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Lactate has long been regarded as one of the key metabolites of mammalian cell cultures. High levels of lactate have clear negative impacts on cell culture processes, and therefore, a great amount of efforts have been made to reduce lactate accumulation and/or to induce lactate consumption in the later stage of cultures. However, there is virtually no report on the impact of lactate depletion after initial accumulation. In this work, we observed that glucose uptake rate dropped over 50% at the onset of lactate consumption, and that catabolism of alanine due to lactate depletion led to ammonium accumulation. We explored the impact of feeding lactate as well as pyruvate to the cultures. In particular, a strategy was employed where CO2 was replaced by lactic acid for culture pH control, which enabled automatic lactate feeding. The results demonstrated that lactate or pyruvate can serve as an alternative or even preferred carbon source during certain stage of the culture in the presence of glucose, and that by feeding lactate or pyruvate, very low levels of ammonia can be achieved throughout the culture. In addition, low levels of pCO2 were also maintained in these cultures. This was in strong contrast to the control cultures where lactate was depleted during the culture, and ammonia and pCO2 build-up were significant. Culture growth and productivity were similar between the control and lactate-fed cultures, as well as various product quality attributes. To our knowledge, this work represents the first comprehensive study on lactate depletion and offers a simple yet effective strategy to overcome ammonia and pCO2 accumulation that could arise in certain cultures due to early depletion of lactate. Biotechnol. Bioeng. 2012; 109:1173-1186. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: 5-Ethylidene-2-norbornene (ENB) polymerization and copolymerization with ethylene (E) catalyzed by constrained geometry catalyst 2-tetramethylcyclopentadienyl-4,6-di-tert-butylphenoxytitanium dichloride (1) were studied in the presence of Al i Bu3 and Ph3CB(C6F5)4 (TIBA/B). The catalyst system shows moderate activity on the homopolymerization of ENB, and higher activity on the copolymerization of E/ENB under atmospheric pressure of ethylene. 1H NMR analysis indicates that ENB was regioselectively incorporated into the copolymer backbone through the endocyclic double bond, leaving the ethylidene double bond unreacted. The ethylidene group contained in the poly(E-co-ENB) was quantitatively converted to the epoxy group with m-chloroperbenzoic acid, producing functionalized poly(E-co-ENB)s. The parent and functionalized copolymers have been characterized using IR, NMR, DSC, and GPC techniques. [Copyright &y& Elsevier]

Abstract: A comparative analysis of electronic structure and stability of endohedral metallofullerenes TM@C24 and TM@C24H12 (TM=Ti, Zr and Hf) is systematically performed with the aid of quantum chemical DFT-B3PW91 approach. Our calculated results show that TM@C24H12 display higher symmetry compared with TM@C24, and all of endohedral metallofullerenes are in a singlet spin state. Thermodynamic data reflect that endohedral metallofullerenes TM@C24 are more stable than TM@C24H12 and the Ti atom is energetically favorable to be encapsulated. However, these TM@C24H12 have higher kinetic stability. The analyses of the vertical electron affinities (VEAs) and vertical ionization potentials (VIPs) indicate the possibilities of accepting electrons of TM@C24H12 become weaker and the possibilities of denoting electrons become stronger. Additionally, natural population analysis presents that the natural charge on TM atoms dramatically increases along with increasing atomic number, and the 5d orbitals of Zr atom and 6d orbitals of Hf atom are significantly involved in their chemical bonding. [Copyright &y& Elsevier]

Animal intestines is considered as a source of lactic acid bacteria (LAB) that have potential to decrease the nitrite level during fermentation of food such as pickles. It was hypothesized that optimized level of LAB has a high capacity to degrade nitrite during Chinese pickle fermentation and benefit a higher acceptability of the Chinese pickle product. This study aims to investigate the performance of a goose intestine-isolated LAB strain G6 under the species Lactiplantibacillus plantarum as a starter culture of Chinese pickles. The results showed that Lactiplantibacillus sp. G6 had a nitrite degradation rate close to 100% under the MRS broth condition of 25 °C, 2% inoculum volume and pH at 5. As a starter culture for Chinese pickle, this strain was able to achieve a higher LABs amount, lower nitrite residue after fermentation, compared with the group without the starter, which implicates its feasibility of applying on fermented food for reducing nitrite level., Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01433-8., Competing Interests: Competing interestsThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© The Korean Society of Food Science and Technology 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

The influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton was studied under controlled hydroponics. The results showed that compared with single nitrate nutrition, solutions with 25/75, 50/50, 75/25 and 100/0 of NH4+/NO3- significantly increased the soluble protein accumulation in leaves and roots of cotton, and the maximum content of soluble protein in leaves and roots appeared respectively in the solution with 50/50 and 75/25 of NH4+/NO3-. The soluble protein content in roots was increased with the increase of NH4+ percentage, but was slightly less in the solution of 100/0 than 75/25, which was probably related to the excess NH4+ limiting boot metabolism. With the increase of NH4+ percentage, the nitrate content in petiole and the nitrate reductase activity in functional blade declined, but ammoniac nitrogen content increased in every organ of cotton. These results showed that foreign nitrogen affected the nitrogen metabolism of cotton in a different way, and the nitrogen absorption by cotton was probably related to different forms of foreign nitrogen.

Objective: To explore new source of skin for burn wound coverage., Methods: Split-thickness consanguineous skin was harvested from New Zealand white rabbit and was soaked in 200 g/L of multi-peptides of Tripterygium wilfordii, 50 g/L of dexamethasonel, on 9 g/L of normal saline solution for 15 - 30 mins, respectively. The consanguineous skin was thereafter grafted onto the whole layer skin defects in filial generation of rabbits with non-consanguineous skin as the control. The survival time and rejection of the grafted skin was observed., Results: The rejection appeared evidently less intense and survived significantly longer (43 +/- 3.5 days) when the consanguineous skin was pretreated by Tripterygium wilfordii. However the grafted consanguineous skin survived for 30 +/- 2.5 days when it was pretreated by dexamethasone. The grafted skin was quickly rejected and survived only for 11 +/- 1.6 days when the skin was pretreated by normal saline or the skin was non-consanguineous., Conclusion: Consanguineous skin possessed partial compatibility with the recipient due to similar antigen, which was beneficial to the its survival, especially after the skin was pretreated.