Variable gravity research facility

Spin and despin requirements; sequence of activities required to assemble the Variable Gravity Research Facility (VGRF); power systems technology; life support; thermal control systems; emergencies; communication systems; space station applications; experimental activities; computer modeling and simulation of tether vibration; cost analysis; configuration of the crew compartments; and tether lengths and rotation speeds are discussed

Putrescine-Mediated Changes in Mammalian Intracellular Polyamine Levels Increase Spermidine/Spermine-N1-Acetyltransferase Activity and Increase Gene Expression of Several Cell Cycle-Related Genes

Polyamines are aliphatic polycations existing in all living organisms and are essential for life. Most organisms synthesize three types of polyamines: putrescine, spermidine, and spermine. Putrescine is the product of the rate-limiting reaction of ornithine decarboxylase (ODC) and the amino acid ornithine. Spermidine and spermine are downstream metabolites sequentially derived from putrescine. In a recent landmark colon cancer chemopreventative clinical trial researchers found that combining alpha-difluoromethylornithine (DFMO), a selective ODC suicide inhibitor, and sulindac, a nonsteroidal anti-inflammatory drug, led to a 70% reduction of recurrence of all adenomas and a 90% reduction of recurrence of advanced and/or multiple adenomas over a 3-year treatment. This study shows that polyamine metabolic enzymes are attractive targets for possible chemotherapeutics. Our previous research has shown that stable ODC overexpression led to increased ODC activity, elevated intracellular putrescine levels with concomitant losses of spermidine and spermine, and increased spermidine/spermine-N1-acetyltransferase (SSAT) activity. Following a genome-wide array analysis on the effects of ODC overexpression in mammalian cell lines, several cell cycle-related genes were found to be upregulated. We investigated whether changes in polyamine levels, polyamine metabolism, and gene expression following stable ODC overexpression could be replicated following treatment with exogenously supplied putrescine. We observed that intracellular putrescine levels following treatment with exogenous putrescine accumulated to levels observed during stable ODC overexpression. These putrescine-mediated changes in intracellular putrescine pools also led to increased mRNA levels and activity of SSAT and to increased gene expression of ID1, c-Jun, and c-Fos in a time- and dose-dependent manner. We also determined that the observed increases in gene expression were mediated by the accumulation of intracellular putrescine independent from the activation of key, rate-limiting polyamine metabolic enzymes. Changes in intracellular polyamine pools, polyamine metabolism, and gene expression following the administration of exogenously supplied putrescine closely resembled the changes observed following stable ODC overexpression

Putrescine-Mediated Changes in Mammalian Intracellular Polyamine Levels Increase Spermidine/Spermine-N1-Acetyltransferase Activity and Increase Gene Expression of Several Cell Cycle-Related Genes

Polyamines are aliphatic polycations existing in all living organisms and are essential for life. Most organisms synthesize three types of polyamines: putrescine, spermidine, and spermine. Putrescine is the product of the rate-limiting reaction of ornithine decarboxylase (ODC) and the amino acid ornithine. Spermidine and spermine are downstream metabolites sequentially derived from putrescine. In a recent landmark colon cancer chemopreventative clinical trial researchers found that combining alpha-difluoromethylornithine (DFMO), a selective ODC suicide inhibitor, and sulindac, a nonsteroidal anti-inflammatory drug, led to a 70% reduction of recurrence of all adenomas and a 90% reduction of recurrence of advanced and/or multiple adenomas over a 3-year treatment. This study shows that polyamine metabolic enzymes are attractive targets for possible chemotherapeutics. Our previous research has shown that stable ODC overexpression led to increased ODC activity, elevated intracellular putrescine levels with concomitant losses of spermidine and spermine, and increased spermidine/spermine-N1-acetyltransferase (SSAT) activity. Following a genome-wide array analysis on the effects of ODC overexpression in mammalian cell lines, several cell cycle-related genes were found to be upregulated. We investigated whether changes in polyamine levels, polyamine metabolism, and gene expression following stable ODC overexpression could be replicated following treatment with exogenously supplied putrescine. We observed that intracellular putrescine levels following treatment with exogenous putrescine accumulated to levels observed during stable ODC overexpression. These putrescine-mediated changes in intracellular putrescine pools also led to increased mRNA levels and activity of SSAT and to increased gene expression of ID1, c-Jun, and c-Fos in a time- and dose-dependent manner. We also determined that the observed increases in gene expression were mediated by the accumulation of intracellular putrescine independent from the activation of key, rate-limiting polyamine metabolic enzymes. Changes in intracellular polyamine pools, polyamine metabolism, and gene expression following the administration of exogenously supplied putrescine closely resembled the changes observed following stable ODC overexpression

Transcriptomic Response of White Lupin Roots to Short-Term Sucrose Treatment

White lupin (Lupinus albus) has become a model plant for understanding plant adaptations to phosphorus (P) and iron (Fe) deficiency, two major limiting factors for plant productivity. In response to both nutrient deficiencies, white lupin forms cluster roots, bottle-brush-like root structures that aid in P and Fe acquisition from soil. While the cluster root function is well-studied, not much is known about the signaling pathways involved in sensing and responding to a P and Fe deficiency. Sucrose has been identified as a long-distance signal sent in increased concentrations from shoot to root in response to both a P and Fe deficiency. Thus, sucrose plays a dual role both as a signal and as a major source of energy for the root. To unravel the responses to sucrose as a signal, we performed an Illumina paired-end cDNA sequencing of white lupin roots treated with sucrose for 20, 40 or 80 min, compared to untreated controls (0 min). We identified 634 up-regulated and 956 down-regulated genes in response to sucrose. Twenty minutes of sucrose treatment showed the most responses, with the ethylene-activated signaling pathway as the most enriched Gene Ontology (GO) category. The number of up-regulated genes decreased at 40 min and 80 min, and protein dephosphorylation became the most enriched category. Taken together, our findings indicate active responses to sucrose as a signal at 20 min after a sucrose addition, but fewer responses and a potential resetting of signal transduction pathways by the dephosphorylation of proteins at 40 and 80 min

The Riddle of the Alien-Citizen: Filipino Migrants as US Nationals and the Anomalies of Citizenship, 1900s–1930s

This article interrogates the classification of Filipino migrants in the United States as US nationals, during the period of American sovereignty in the Philippines. It reveals the history behind this legal status by looking at two broad aspects. Firstly, this article narrates the circumstances that led to the creation of Philippine citizenship even if the Philippines was not a sovereign state. This citizenship had legal force only because Filipinos owed allegiance to the US, and because of this allegiance Filipinos could not be classed as aliens and denied entry to the US at a time of stiff racial barriers. Secondly, this article examines how the range of Filipino migrant responses to racial prejudice and violence in the US, especially in the late 1920s and the 1930s, pushed the limits to reveal the contradictions of both Philippine and US citizenships. Because Filipinos asserted their entitlement as US nationals, US government officials eventually admitted the anomalous exclusion of Filipinos from US citizenship. An illuminating case is the successful claim of Filipino fishers in Alaska for their traditional fishing rights not to be curtailed as a local territorial law had intended