Reuben

https://digitalcommons.library.umaine.edu/mmb-vp/6563/thumbnail.jp

Pansies for Thought : Waltz

https://digitalcommons.library.umaine.edu/mmb-ps/2528/thumbnail.jp

Geoffrey Keating, William Thomas, Raymond Williams, and the Terminology of Folklore: 'Bealoideas' as a 'Keyword'

Article

Identification of an \u3ci\u3eEscherichia coli\u3c/i\u3e Genetic Locus Involved in Thermoregulation of the \u3ci\u3epap\u3c/i\u3e Operon

We previously showed, using a single-copy papBAp-lac fusion (previously designated papBA-lac), that pyelonephritis-associated pili (pap) pilin gene transcription is subject to both phase variation and thermoreg- ulatory control mechanisms (L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, and D. A. Low, EMBO J. 8:613-620, 1989). At 37°C, Escherichia coli strains carrying the papBAp-lac fusion displayed both Lac\u27 and Lac- colony phenotypes. In contrast, at 23°C, colonies displayed a uniform Lac- phenotype, suggesting that pilin was not transcribed at this temperature. In this study, a strain carrying the papBAp-lac fusion was subjected to mini-TnlO (mTnlO) mutagenesis to isolate mutants that could initiate transcription of pilin at the nonpermissive temperature. Two classes of thermoregulatory mutants were identified in which the mTnlO mutation was linked to the mutant phenotype. Class I mutants displayed a phase variation phenotype at both 37°C and 23°C, whereas class II mutants displayed a uniform Lac\u27 colony phenotype at both temperatures. Preliminary analysis of these mutants showed that the mTnlO insertions in the class I mutants were chromosomally located, whereas the mTnlO insertions in the class II mutants were located within the papBAp-lac fusion phage. Southern blot analysis of the class I mutants demonstrated that mTnlO was present in the same 5.9-kilobase Sall DNA fragment in each mutant. Two of the class I mTnlO mutations were mapped to approximately 23.4 min on the E. coli K-12 chromosome. The locus defined by the class I mTnlO mutations was designated tcp, for thermoregulatory control ofpap. Analysis of phase transition rates of the class I mutants showed that the phase-off (Lac-)\u3e phase-on (Lac\u27) transition rates were higher than those observed with the nonmutant E. coli strain

Phase-Variation of Pyelonephritis-Associated Pili in \u3ci\u3eEscherichia coli\u3c/i\u3e: Evidence for Transcriptional Regulation

The regulation of pyelonephritis-associated pill (pap) pflin gene transcription has been examined using two operons (pap-17 and pap-21) isolated from the pyelonephritogenic Escherichia coli strain C1212. DNA sequence analysis and E.coli minicell analysis were used to map two genes (papB and papl) within the pilin regulatory regions of both pap-17 and pap-21, and the protein products of these genes were identified. Pilin transcription, initiated at the papBA promoter, was monitored by constructing single copy operon fusions with lacZYA in E.coli K-12. Inocula- tion of E.coli (pap\u27-lac) strains onto solid M9 minimal medium containing glycerol and the Lac indicator X-gal (M9-Glycerol) yielded both Lac\u27 and Lac- colony phenotypes. The Lac\u27 (\u27phase on\u27) and Lac- (\u27phase off\u27) phenotypes were heritable since reinoculation of M9-Glycerol with bacteria picked from Lac\u27 colonies gave rise to a much higher fraction of Lac\u27 colonies than reinoculation of M9-Glycerol with bacteria picked from Lac- colonies. Measurement of phase transition rates for E.coli (pap17\u27-lac) inoculated onto M9-Gly- cerol showed that the Lac - -Lac+ transition frequency (1.57 x 10-4/cell/generation) was reduced 35-fold when cells were inoculated onto minimal medium containing glucose (M9-Glucose). However, the Lac+-Lac- transition frequency obtained using M9-Glycerol (2.60 x 10-2/cell/generation) was 1.4-fold lower compared to results obtained with M9-Glucose. In contrast, lowering the incubation temperature of E.coli (pap17\u27-lac) cultures from 37°C to 23\u27C caused all cells to shift to the Lac- state. Together, our results strongly indicate that pap pfli phase-variation is transcriptionally regulated and show that phase-variation is responsive to changes in the bacterial environment

Large?scale Investments in Agriculture in India

Public investment in agriculture has significant poverty?reducing effects. This article attempts to analyse trends in agricultural investments in India between the 1950s and the 2000s. It argues that public investment and expenditure on agriculture in India have grown only slowly and have not decisively increased even after more than 60 years of independence. While public capital formation and expenditure do show a moderate rise in the 2000s, a revival of India's agricultural growth requires a far greater thrust to public spending. Major and medium irrigation projects require special attention, as irrigation is instrumental not just in raising yields, but also the number of days of employment for labourers. Increasing public investment in agricultural research and extension is central to bridging the yield gap that persists. Formal credit flows to agriculture have to specifically target small and marginal farmers, and emphasis should move away from generating agricultural growth by channelling credit to agri?business firms and corporate players in agriculture. If India's second green revolution has to contribute to an accelerated reduction of poverty, hunger and malnourishment, it undoubtedly has to be a state?led project

Re-localization of Cellular Protein SRp20 during Poliovirus Infection: Bridging a Viral IRES to the Host Cell Translation Apparatus

Poliovirus IRES-mediated translation requires the functions of certain canonical as well as non-canonical factors for the recruitment of ribosomes to the viral RNA. The interaction of cellular proteins PCBP2 and SRp20 in extracts from poliovirus-infected cells has been previously described, and these two proteins were shown to function synergistically in viral translation. To further define the mechanism of ribosome recruitment for the initiation of poliovirus IRES-dependent translation, we focused on the role of the interaction between cellular proteins PCBP2 and SRp20. Work described here demonstrates that SRp20 dramatically re-localizes from the nucleus to the cytoplasm of poliovirus-infected neuroblastoma cells during the course of infection. Importantly, SRp20 partially co-localizes with PCBP2 in the cytoplasm of infected cells, corroborating our previous in vitro interaction data. In addition, the data presented implicate the presence of these two proteins in viral translation initiation complexes. We show that in extracts from poliovirus-infected cells, SRp20 is associated with PCBP2 bound to poliovirus RNA, indicating that this interaction occurs on the viral RNA. Finally, we generated a mutated version of SRp20 lacking the RNA recognition motif (SRp20ΔRRM) and found that this protein is localized similar to the full length SRp20, and also partially co-localizes with PCBP2 during poliovirus infection. Expression of this mutated version of SRp20 results in a ∼100 fold decrease in virus yield for poliovirus when compared to expression of wild type SRp20, possibly via a dominant negative effect. Taken together, these results are consistent with a model in which SRp20 interacts with PCBP2 bound to the viral RNA, and this interaction functions to recruit ribosomes to the viral RNA in a direct or indirect manner, with the participation of additional protein-protein or protein-RNA interactions

Rapid identification viruses from nasal pharyngeal aspirates in acute viral respiratory infections by RT-PCR and electrospray ionization mass spectrometry

a b s t r a c t Diagnosis of the etiologic agent of respiratory viral infection relies traditionally on culture or antigen detection. This pilot evaluation compared performance characteristics of the RT-PCR and electrospray ionization mass spectrometry (RT-PCR/ESI-MS) platform to conventional virologic methods for identifying multiple clinically relevant respiratory viruses in nasopharyngeal aspirates. The RT-PCR/ESI-MS respiratory virus surveillance kit was designed to detect respiratory syncytial virus, influenza A and B, parainfluenza types 1-4, adenoviridae types A-F, coronaviridae, human bocavirus, and human metapneumovirus. Patients (N = 192) attending an emergency department during the 2007-2008 respiratory season consented, and "excess" frozen archived nasopharyngeal aspirates were analysed; 46 were positive by conventional virology and 69 by RT-PCR/ESI-MS, among which there were six samples with multiple viral pathogens detected. The sensitivity and specificity of the assay were 89.1% and 80.3%, respectively. Additional viruses that were not identified by conventional virology assays were detected (4 human bocaviruses and 7 coronaviruses). Samples in which the RT-PCR/ESI-MS results disagreed with conventional virology were sent for analysis by a third method using a commercial RT-PCR-based assay, which can identify viruses not detectable by conventional virologic procedures. Time to first result of RT-PCR/ESI-MS was 8 h. RT-PCR/ESI-MS demonstrated capacity to detect respiratory viruses identifiable and unidentifiable by conventional methods rapidly