2,042 research outputs found
Race Before Nation: African American Activists and Their Response to the War in Vietnam
The escalation of America’s war in Vietnam coincided with the culmination of the long-fought civil rights movement. Most, if not all, Black leaders voiced opposition to the Vietnam War before the end of the 1960s. However, it was the racially disproportionate statistics in the military in the early years of the conflict to activists fracture within the movement. Regardless of when individual Black leaders spoke out, what they specifically spoke out against, and how radically they voiced opposition, Black leaders put race before nation when voicing an opinion on Vietnam
Construction Cost Sensitivity of a Lignocellulosic Ethanol Biorefinery
The technology has been developed to convert feedstock with cellulose content into ethanol. However, ethanol produced from cellulosic feedstock is the same as ethanol distilled from grain. The objective of research is to determine the price per gallon of ethanol needed so that producing lignocellulosic based ethanol become economically feasible.Environmental Economics and Policy, Production Economics,
Hemoglobin genotype has minimal influence on the physiological response of juvenile atlantic cod (Gadus morhua) to environmental challenges
Hemoglobin (Hb) polymorphism in cod is associated with temperature‐related differences in biogeographical distribution, and several authors have suggested that functional characteristics of the various hemoglobin isoforms (HbIs) directly influence phenotypic traits such as growth rate. However, no study has directly examined whether Hb genotype translates into physiological differences at the whole animal level. Thus, we generated a family of juvenile Atlantic cod consisting of all three main Hb genotypes (HbI‐1/1, HbI‐2/2, and HbI‐1/2) by crossing a single pair of heterozygous parents, and we compared their metabolic and cortisol responses to an acute thermal challenge (10°C to their critical thermal maximum [CTM] or 22°C, respectively) and tolerance of graded hypoxia. There were no differences in routine metabolism (at 10°C), maximum metabolic rate, metabolic scope, CTM (overall mean 22.9° ± 0.2°C), or resting and poststress plasma cortisol levels among Hb genotypes. Further, although the HbI‐1/1 fish grew more (by 15%–30% during the first 9 mo) when reared at 10° ± 1°C and had a slightly enhanced hypoxia tolerance at 10°C (e.g., the critical O2 levels for HbI‐1/1, HbI‐2/2, and HbI‐1/2 cod were 35.56% ± 1.24%, and 40.20% ± 1.99% air saturation, respectively), these results are contradictory to expectations based on HbI functional properties. Thus, our findings (1) do not support previous assumptions that growth rate differences among cod Hb genotypes result from a more efficient use of the oxygen supply—that is, reduced standard metabolic rates and/or increased metabolic capacity—and (2) suggest that in juvenile cod, there is no selective advantage to having a particular Hb genotype with regards to the capacity to withstand ecologically relevant environmental challenges.<br /
Isolation and Analysis of Extracellular Vesicles from Lactic Acid Bacteria
Extracellular Vesicles, also referred to as EVs, are spherical lipid membrane-bound vesicles produced by both Gram positive and Gram negative bacteria. These vesicles are secreted into the extracellular space and play important functions in cellular and host communication, elimination of competitors, virulence, detoxification of environmental stress, and nutrition sensing. They are often packed with proteins, enzymes, lipids, and nucleic acids like DNA or RNA molecules among other biological entities. Streptococcus thermophilus is a lactic acid bacterium (LAB), inhabiting the human digestive tract, that has been shown to produce EVs. The bacterial flora has a great impact on the host immune system, metabolism, and neurological processes, however, not a lot is known about the biochemical pathways behind this impact. Since extracellular vesicles are involved in host communication, they play a key role in the impact that bacterial flora has on the biochemical processes of a host. Therefore S. Thermophilus was grown aerobically at 37° C in M17 media, two other LABs were grown including Lactobacillus acidophilus, and Lactobacillus bulgaricus. The extracellular vesicles will then be isolated through centrifugation, then the EVs content will be analyzed further. Size comparison can be conducted using gel electrophoresis, on various RNA molecules hypothesized to be held within the membranes of EVs. A previous study in this lab isolated the AsdS sRNA molecule, that is 152 base pairs in length, and is involved in quorum sensing. This gene is conserved among Streptococcus species and can be observed in S. pyogenes as the MarS. Since S. thermophilus is a non-pathogenic species the Asd gene cannot be involved in virulence as MarS is responsible for virulence in S. pyogenes. Based on functional predictions, AsdS is responsible for intraspecies communication, biofilm formation, and transport
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A Multinational Analysis of Mutations and Heterogeneity in PZase, RpsA, and PanD Associated with Pyrazinamide Resistance in M/XDR Mycobacterium tuberculosis.
Pyrazinamide (PZA) is an important first-line drug in all existing and new tuberculosis (TB) treatment regimens. PZA-resistance in M. tuberculosis is increasing, especially among M/XDR cases. Noted issues with PZA Drug Susceptibility Testing (DST) have driven the search for alternative tests. This study provides a comprehensive assessment of PZA molecular diagnostics in M/XDR TB cases. A set of 296, mostly XDR, clinical M. tuberculosis isolates from four countries were subjected to DST for eight drugs, confirmatory Wayne's assay, and whole-genome sequencing. Three genes implicated in PZA resistance, pncA, rpsA, and panD were investigated. Assuming all non-synonymous mutations cause resistance, we report 90% sensitivity and 65% specificity for a pncA-based molecular test. The addition of rpsA and panD potentially provides 2% increase in sensitivity. Molecular heterogeneity in pncA was associated with resistance and should be evaluated as a diagnostic tool. Mutations near the N-terminus and C-terminus of PZase were associated with East-Asian and Euro-American lineages, respectively. Finally, Euro-American isolates are most likely to have a wild-type PZase and escape molecular detection. Overall, the 8-10% resistance without markers may point to alternative mechanisms of resistance. Confirmatory mutagenesis may improve the disconcertingly low specificity but reduce sensitivity since not all mutations may cause resistance
Management of Optaflexx in Feedlots that Sort Cattle prior to Market
One hundred and thirty five steers from were used in a study to compare strategies for managing Optaflexx in feedlots that sort cattle just prior to market. The pens were assigned to one of two Optaflexx management treatments. Two pens were each assigned to each treatment. The Optaflexx management treatments were: 1) Topped Out (TO), where half the cattle in each pen were sorted without being fed Optaflexx. The remaining cattle were fed Optaflexx for 28 days, or 2) Sorted Early (SE), where market timing decisions were made more than 28 days prior to the first marketing so that Optaflexx could be fed to all of the cattle. Feed consumption levels and patterns were not affected by sorting cattle early into market outcome groups. There were no differences in performance between the two sorting treatments. Cattle in the SE treatment had significantly larger ribeye areas. Based on the results of this study sorting cattle into market outcome groups prior to the last 28 days of feeding of the first group to be marketed so that Optaflexx can be fed to all of the cattle in the pen is a viable alternative to only feeding Optaflexx to the “last draft” to be marketed
Effect of Synovex Choice Implant on Performance and Carcass Traits of Steer Calves
As marketing of fed cattle has evolved over the past few years, technologies that improve performance and lower cost with the least effect on carcass quality have become more important. One such technology is the intermediate dosage combination implant. These implants combine TBA and estrogen for additive growth response, but at a lower dosage that may reduce potential negative effects of combination implants on carcass quality. Intermediate dosage implants have been used to provide a more aggressive arrival implant for feedlot cattle, or a more conservative terminal implant depending on the goals of the manager. With the recent clearance of Synovex Choice for feedlot steers, the cattle feeder now has two options relative to intermediate dosage combination implants, Synovex Choice and Revalor IS. This study was designed to compare two practical implant combinations—Synovex Choice implanted initially and reimplanted, and Synovex S implanted initially and reimplanted with Revalor IS
Effect of Yeast Supplement on Performance of Steer Calves
The effect of Prosponse1 yeast supplement fed to newly arrived steers was evaluated at the ISU Armstrong Research Farm near Lewis, Iowa. Four pens of approximately 32 head were fed similar diets with 2 pens receiving yeast supplement and 2 pens not. Calves were weighed on delivery to the feedlot and allocated on weight and sire. Calves were on test 34 days. There was no effect on daily gain or feed to gain. Dry matter intake trended higher for the yeast supplemented calves (P=.10). These data suggest that yeast supplement may improve dry matter intake in newly arrived feedlot calves. Yeast supplements have been evaluated in dairy cattle but have not been evaluated in newly arrived feedlot calves
Gene doctoring: a method for recombineering in laboratory and pathogenic Escherichia coli strains
Background: Homologous recombination mediated by the lambda-Red genes is a common method for making chromosomal modifications in Escherichia coli. Several protocols have been developed that differ in the mechanisms by which DNA, carrying regions homologous to the chromosome, are delivered into the cell. A common technique is to electroporate linear DNA fragments into cells. Alternatively, DNA fragments are generated in vivo by digestion of a donor plasmid with a nuclease that does not cleave the host genome. In both cases the lambda-Red gene products recombine homologous regions carried on the linear DNA fragments with the chromosome. We have successfully used both techniques to generate chromosomal mutations in E. coli K-12 strains. However, we have had limited success with these lambda-Red based recombination techniques in pathogenic E. coli strains, which has led us to develop an enhanced protocol for recombineering in such strains. \ud
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Results: Our goal was to develop a high-throughput recombineering system, primarily for the coupling of genes to epitope tags, which could also be used for deletion of genes in both pathogenic and K-12 E. coli strains. To that end we have designed a series of donor plasmids for use with the lambda-Red recombination system, which when cleaved in vivo by the I-SceI meganuclease generate a discrete linear DNA fragment, allowing for C-terminal tagging of chromosomal genes with a 6xHis, 3xFLAG, 4xProteinA or GFP tag or for the deletion of chromosomal regions. We have enhanced existing protocols and technologies by inclusion of a cassette conferring kanamycin resistance and, crucially, by including the sacB gene on the donor plasmid, so that all but true recombinants are counter-selected on kanamycin and sucrose containing media, thus eliminating the need for extensive screening. This method has the added advantage of limiting the exposure of cells to the potential damaging effects of the lambda-Red system, which can lead to unwanted secondary alterations to the chromosome. \ud
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Conclusion: We have developed a counter-selective recombineering technique for epitope tagging or for deleting genes in E. coli. We have demonstrated the versatility of the technique by modifying the chromosome of the enterohaemorrhagic O157:H7 (EHEC), uropathogenic CFT073 (UPEC), enteroaggregative O42 (EAEC) and enterotoxigenic H10407 (ETEC) E. coli strains as well as in K-12 laboratory strains
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