169 research outputs found
“I can’t learn when I’m hungry”: Responding to U.S. college student basic needs insecurity in pedagogy and praxis
Food insecurity and other basic needs insecurities were pressing concerns for U.S. college students prior to the COVID-19 crisis and are even more so now. These issues disproportionately impact minoritized students, making addressing basic needs an issue of educational equity. As feminist teacher-scholars, we reflect in this essay on what it means to teach in the context of student basic needs insecurities, drawing on our experiences from launching an interdisciplinary initiative dedicated to combatting food insecurity on our campus. In doing so, we seek to catalyze changes within and beyond the classroom to better support students
Semicontinuous Bioreactor Production of Recombinant Butyrylcholinesterase in Transgenic Rice Cell Suspension Cultures.
An active and tetrameric form of recombinant butyrylcholinesterase (BChE), a large and complex human enzyme, was produced via semicontinuous operation in a transgenic rice cell suspension culture. After transformation of rice callus and screening of transformants, the cultures were scaled up from culture flask to a lab scale bioreactor. The bioreactor was operated through two phases each of growth and expression. The cells were able to produce BChE during both expression phases, with a maximum yield of 1.6 mg BChE/L of culture during the second expression phase. Cells successfully regrew during a 5-day growth phase. A combination of activity assays and Western blot analysis indicated production of an active and fully assembled tetramer of BChE
A novel plant cell culture platform for semicontinous production of recombinant proteins: Butyrylcholinesterase as a case study
In this paper we describe a novel biomanufacturing production platform that utilizes transgenic rice cell suspension cultures for efficient semicontinuous cell culture (SCC) production of recombinant proteins. The production platform utilizes a metabolically regulated promoter, a secretion signal peptide that enables secretion out of the cell for ease of recovery/purification, coupled with an efficient semicontinuous operational strategy that allows independent optimization of growth and production phases. In addition, long term operation (up several months1) is possible by maintaining viable biomass within the bioreactor, thereby reducing the need for long seed trains, as well as minimizing turn-around time, CIP and SIP operations, chemicals and energy. This platform offers a number of advantages over traditional methods for production of recombinant therapeutic proteins that use E. coli, yeast or mammalian cell cultures, while still retaining the ability to meet cGMP regulatory requirements under well-controlled, reproducible production conditions. Traditional methods for production of biologics use genetically modified E. coli, yeast, insect or mammalian cell cultures in bioreactor systems. For applications where a human therapeutic protein (monoclonal antibodies, vaccines, bioscavengers, replacement biologics) produced under strict cGMP conditions are required, plant cell cultures offer a number of advantages over currently used bioreactor-based systems, including low risk of contamination by mammalian viruses, blood-borne pathogens, prions or bacterial endotoxins or mycoplasma, the ability to perform complex glycosylation, ease of culturing compared with other higher eukaryotic hosts, the ability to target the product to the extracellular medium, and the ability to grow in simple, low cost, chemically defined and animal component-free medium. In this paper we describe the specific characteristics of the rice cell suspension culture that make them particularly useful for continuous operation and superior to other hosts including their slow death rates, growth in small aggregates, limited secretome, and robustness under culture conditions. In addition, the regulatory pathway for plant-based recombinant biologics for human therapeutic use has now been established. ElelysoTM, produced in carrot cell suspension in batch culture by Protalix Biotherapeutics and Pfizer, Inc. for treatment of Gaucher disease was approved by the FDA in May 20122, 3.
The transgenic rice cell culture system is operated in a cyclical, semicontinuous operation as shown in Figure 1. Note that gravity sedimentation within the bioreactor can be used to separate the plant cell aggregates from the liquid phase in Steps 3 and 6, and that the product collected in Step 6 can be purified either using a batch downstream strategy or collected to feed a continuous downstream process.
Results will be presented for semicontinuous production of butyrylcholinesterase, a bioscavenger for organophosphorus nerve agents such as sarin, using the metabolically regulated transgenic rice cell culture in 5 L bioreactors
Reducing Poverty in California…Permanently
If California were to seriously commit to equalizing opportunity and reducing poverty, how might that commitment best be realized?
This is of course a hypothetical question, as there is no evidence that California is poised to make such a serious commitment, nor have many other states gone much beyond the usual lip-service proclamations. There are many reasons for California’s complacency, but an important one is that most people think that poverty is intractable and that viable solutions to it simply don’t exist.
When Californians know what needs to be done, they tend to go forward and get it done. When, for example, the state’s roads are in disrepair, there are rarely paralyzing debates about exactly how to go about fixing them; instead we proceed with the needed repairs as soon as the funds to do so are appropriated. The same type of sure and certain prescription might appear to be unavailable when it comes to reducing poverty. It is hard not to be overwhelmed by the cacophony of voices yielding a thick stream of narrow-gauge interventions, new evaluations, and piecemeal proposals.1
Although the research literature on poverty is indeed large and may seem confusing, recent advances have in fact been so fundamental that it is now possible to develop a science-based response to poverty. In the past, the causes of poverty were not well understood, and major interventions, such as the War on Poverty, had to be built more on hunch than science. It is an altogether different matter now. The causes of poverty are well established, and the effects of many possible policy responses to poverty are likewise well established. The simple purpose of this essay is to assemble these advances into a coherent plan that would, if implemented, reduce poverty in California substantially
PKC-omerga and HIV-1 transcriptional regulator Tat co-exist at the LTR promoter in CD4<sup>+</sup> T cells
PKCtheta is essential for the activation of CD4+ T cells. Upon TCR/CD28 stimulation, PKCtheta is phosphorylated and migrates to the immunological synapse, inducing the activation of cellular transcription factors such as NF-kB and kinases as ERK that are critical for HIV-1 replication. We previously demonstrated that PKCtheta is also necessary for HIV-1 replication but the precise mechanism is unknown. Efficient HIV-1 transcription and elongation is absolutely dependent on the synergy between NF-kB and the viral regulator Tat. Tat exerts its function by binding a RNA stem-loop structure proximal to the viral mRNA cap site termed TAR. Besides, due to its effect on cellular metabolic pathways, Tat causes profound changes in infected CD4+ T cells such as the activation of NF-kB and ERK. We hypothesized that the aberrant up-regulation of Tat-mediated activation of NF-kB and ERK occurred through PKCtheta signaling. In fact, Jurkat TetOff cells with stable and doxycycline-repressible expression of Tat (Jurkat-Tat) expressed high levels of mRNA for PKCtheta. In these cells, PKCtheta located at the plasma membrane was phosphorylated at T538 residue in undivided cells, in the absence of stimulation. Treatment with doxycycline inhibited PKCtheta phosphorylation in Jurkat-Tat, suggesting that Tat expression was directly related to the activation of PKCtheta. Both NF-kB and Ras/Raf/MEK/ERK signaling pathway were significantly activated in Jurkat-Tat cells, and this correlated with high transactivation of HIV-1 LTR promoter. RNA interference for PKCtheta inhibited NF-kB and ERK activity, as well as LTR-mediated transactivation even in the presence of Tat. In addition to Tat-mediated activation of PKCtheta in the cytosol, we demonstrated by sequential ChIP that Tat and PKCtheta coexisted in the same complex bound at the HIV-1 LTR promoter, specifically at the region containing TAR loop. In conclusion, PKCtheta-Tat interaction seemed to be essential for HIV-1 replication in CD4+ T cells and could be used as a therapeutic target
Why is there so much Poverty in California? The Causes of California’s Sky-High Poverty and the Evidence Behind the Equal Opportunity Plan for Reducing It
The purpose of this report is to describe the current state of poverty in California, to discuss concrete steps that could be taken to reduce poverty in California, and to present the best available evidence on the likely effects of those steps. We take on an important but infrequently-posed question: If California were to seriously commit to reducing poverty, how might that commitment best be realized?
This is of course a hypothetical question, as there is no evidence that California is poised to make such a serious commitment, nor have many other states gone much beyond the usual lip service proclamations. It is nonetheless especially striking that California, the highest-poverty state in the country, has not rushed in to rectify the matter.1
There are many reasons for this seeming complacency, but an especially important one is that most people think that poverty is intractable and that viable solutions to it simply don’t exist. When Californians know what needs to be done, they tend to go forward and get it done. When, for example, the state’s roads are in disrepair, there are rarely paralyzing debates about exactly how to go about fixing them; and instead we proceed with the needed repairs as soon as the funds to do so are appropriated. The same type of sure and certain prescription might appear to be unavailable when it comes to fixing poverty. It is hard not to be overwhelmed by the cacaphony of voices yielding a thick stream of narrow-gauge interventions, new evaluations, and piecemeal proposals.
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