Recommendations to Create a Systemic Approach to Improving the Teaching and Learning of Iowa History in Iowa’s K-12 Schools / Iowa History Advisory Council (2016)

Report from the Iowa History Advisory Council on the following goals related to the teaching of Iowa history: Identify the current status of the teaching of Iowa history and the resources available regarding K-12 Iowa history instruction. Identify current materials that are dedicated to the teaching of Iowa history at the K-12 level. Study how other states and organizations implement state and local history. Study best practices for the teaching and learning of state and local history. Develop appropriate academic standards related to Iowa history. Provide recommendations to advance the study of Iowa history at the K-12 level.

UNPROVEN INNOVATION: IPADS IN K-12 ENVIRONMENTS

Nationally, the education sector spends more than 5 billion dollars annually on digital tools, “yet seldom are technology solutions factored into any viable equation for improving student academic achievement” (Moersch, 2014, p. ix). Consider the following case in point: In July 2014, Apple announced that in just 3 years, the company had sold more than13 million iPads to educational institutions worldwide (Cavanagh, 2014). Put into perspective, that represents more than 5.2 billion dollars spent by the education industry to purchase iPads, which is the equivalent of the annual salaries of 89,655 teachers (“High School Teacher: Salary,” 2014). Despite such vast expenditures, there have been very few attempts to evaluate the efficacy of these digital tools on improving academic achievement. This research involved a quantitative data review of participant (student and teacher) survey data to explore one of the country’s largest K-12 iPad implementation undertakings in an effort to identify (a) best practices and (b) lessons learned from implementing the iPad into K-12 educational environments. It should be noted that the school system forming the basis of this research already had administered and collated the surveys used in this study.

K-12 Technology Initiative Report

In Fiscal Year 2014-15 the General Assembly funded with lottery fund revenues the K-12 Technology Initiative. The Initiative has three objectives: to improve external connections to schools; to improve internal connections within schools; and to develop or expand one-to-one computing. There is also a summary of the school district and school responses to questions on the South Carolina Technology Counts Survey for the 2015-16 reporting period that pertain directly to the K-12 Technology Initiative.

Transitions to K–12 Education Systems: Experiences from Five Case Countries

Currently more than 140 countries offer, or are in transition to, what has become the international norm for pre-tertiary education, namely a kindergarten through grade 12 (K–12) school education system—kindergarten because of the preponderance of research asserting the long-term learning and social benefits of school readiness programs; and 12 years of primary and secondary schooling due to the time needed to acquire the knowledge and skills sets necessary for 21st century university education, postsecondary training, or decent1 work. This desk study2 conveys the experiences of four countries and one province in preparing and implementing a transition to a K–12 school education system: Mongolia, Ontario (Canada), the Philippines, Poland, and Turkey. Looking at K–12 transition in countries and systems that vary as broadly as this set enables common threads to stand out and divergent options to be noted.

Relação dos sistemas de reparo de DNA em Escherichia coli K-12 com resistência a antibióticos, características adesivas e formação de biofilme

As espécies reativas de oxigênio (ERO) são geradas durante o metabolismo celular normal e podem produzir vários danos oxidativos no DNA, tais como lesões nas bases nitrogenadas ou sítios apurínico/apirimidínico (AP). Essas lesões podem acarretar acúmulo de sítios de mutações, caso esses danos não sejam reparados. Entretanto, as bactérias possuem vários mecanismos de defesa contra as ERO que desempenham um importante papel na manutenção da fisiologia. O objetivo deste trabalho foi o de avaliar se sistemas enzimáticos, como o reparo por excisão de bases (BER), sistema SOS e SoxRS, interferem em respostas como a sensibilidade aos antibióticos, aderência das células bacterianas a superfícies bióticas ou abióticas e formação de biofilme. Os mutantes utilizados no presente estudo são todos derivados de Escherichia coli K-12 e os resultados obtidos mostraram que, dos mutantes BER testados, o único que apresentou diferença no perfil de sensibilidade aos antimicrobiamos em relação à cepa selvagem (AB1157) foi o mutante xthA- (BW9091), deficiente em exonuclease III. No teste de aderência qualitativo realizado com linhagem de células HEp-2 (originária de carcinoma de laringe humana) foi observado que onze cepas da nossa coleção, apresentaram um padrão denominando like-AA, contrastando com o que era esperado para as cepas de E. coli utilizadas como controle negativo, que apresentam aderência discreta sem padrão típico. A aderência manose-sensível via fímbria do tipo I avaliada nesse estudo mostrou que essa fimbria, possui um papel relevante na intensidade da aderência e filamentação nessas cepas estudas. A filamentação é uma resposta SOS importante para que o genoma seja reparado antes de ser partilhado pelas células filhas. Além disso, com relação à formação de biofilme, oito cepas apresentaram um biofilme forte sendo que essa resposta não foi acompanhada pelo aumento da intensidade de filamentação. Nossos resultados em conjunto sugerem o envolvimento de estresse oxidativo na definição de parâmetros como sensibilidade a antimicrobianos, padrão e intensidade de aderência, filamentação e formação de biofilme nas amostras de E. coli K-12 avaliadas neste trabalho. Sugerimos que a aderência gera estresse oxidativo causando danos no DNA, o que leva a indução do sistema SOS resultando na resposta de filamentação observada.

Efeitos genotóxicos e indução do SOS em mutantes derivados de Escherichia coli K-12 durante o processo de interação com superfícies bióticas e abióticas

A célula epitelial é o primeiro contato entre os micro-organismos e o hospedeiro. Essa interação pode levar a produção de diversas citocinas, quimiocinas, moléculas inflamatórias e também estimular a geração de espécies reativas de oxigênio (ERO). Neste trabalho avaliamos se a interação com as células HEp-2 poderia ser genotóxica para os mutantes derivados de Escherichia coli K-12 deficientes em algumas enzimas que fazem parte do sistema de reparo por excisão de base (BER). Além disto, avaliamos a expressão do sistema SOS, que é induzido pela presença de danos no genoma bacteriano. Os resultados obtidos mostraram a presença de filamentos, na interação com células HEp-2, principalmente, no mutante xthA (BW9091) e no triplo mutante xthA nfo nth (BW535). Quando a interação foi quantificada na ausência da D-manose, observamos um aumento das bactérias aderidas. Além disto, a quantidade e o tamanho dos filamentos também aumentaram, mostrando que as adesinas manose-sensíveis estavam envolvidas na filamentação bacteriana. Para comprovar se o aumento da filamentação observada neste ensaio foram uma consequência da indução do sistema SOS, desencadeada pela interação com as células HEp-2, quantificamos a expressão do SOS, na presença e na ausência da D-manose. De fato, observamos que a indução do SOS na ausência da D-manose foi maior, quando comparada, com o ensaio realizado na presença de D-manose. Além disto, observamos que a ausência de xthA foi importante para o aumento da filamentação observada na ausência de D-manose. Diante destes resultados, verificamos se a resposta de filamentação ocorreria quando as bactérias interagiam com uma superfície abiótica como o vidro. Observamos também inúmeros filamentos nos mutantes BER, BW9091 e BW535, quando comparados a cepa selvagem AB1157. Essa filamentação foi associada à indução do SOS, em resposta a interação das bactérias com o vidro. Em parte a filamentação e a indução do SOS observadas na interação ao vidro, foram associadas à produção de ERO. Quantificamos também o número de bactérias aderidas e observamos que as nossas cepas formavam biofilmes moderados. Contudo, a formação de biofilme dependia da capacidade da bactéria induzir o sistema SOS, tanto em aerobiose como em anaerobiose. A tensão do oxigênio foi importante para interação dos mutantes BER, uma vez que os mutantes BW9091 e BW535 apresentaram uma quantidade de bactérias aderidas menor em anaerobiose. Contudo, a diminuição observada não estava vinculada a morte dos mutantes BER. Também realizamos microscopia de varredura na cepa selvagem e nos mutantes, BW9091 e BW535 e confirmamos que as três cepas formavam biofilmes tanto em aerobiose como em anaerobiose. Observamos uma estrutura sugestiva de matriz extracelular envolvendo os biofilmes da cepa selvagem AB1157 e do mutante BW9091. No entanto, a formação desta estrutura por ambas as cepas dependia da tensão de oxigênio, pois nos biofilmes formados em anaerobiose essa estrutura estava ausente. Em conclusão, mostramos que na interação das bactérias com a superfície biótica e abiótica, ocorreu lesão no genoma, com indução do SOS e a resposta de filamentação associada.

Documenta 12. Education

Sin resumen

Functional analysis of the large periplasmic loop of the Escherichia coli K-12 WaaL O-antigen ligase

WaaL is a membrane enzyme implicated in ligating undecaprenyl-diphosphate (Und-PP)-linked O antigen to lipid A-core oligosaccharide. We determined the periplasmic location of a large (EL5) and small (EL4) adjacent loops in the Escherichia coli K-12 WaaL. Structural models of the EL5 from the K-12, R1 and R4 E. coli ligases were generated by molecular dynamics. Despite the poor amino acid sequence conservation among these proteins, the models afforded similar folds consisting of two pairs of almost perpendicular alpha-helices. One alpha-helix in each pair contributes a histidine and an arginine facing each other, which are highly conserved in WaaL homologues. Mutations in either residue rendered WaaL non-functional, since mutant proteins were unable to restore O antigen surface expression. Replacements of residues located away from the putative catalytic centre and non-conserved residues within the centre itself did not affect ligation. Furthermore, replacing a highly conserved arginine in EL4 with various amino acids inactivates WaaL function, but functionality reappears when the positive charge is restored by a replacement with lysine. These results lead us to propose that the conserved amino acids in the two adjacent periplasmic loops could interact with Und-PP, which is the common component in all WaaL substrates.

Functional analysis of predicted coiled-coil regions in the Escherichia coli K-12 O-antigen polysaccharide chain length determinant Wzz

Wzz is a membrane protein that determines the chain length distribution of the O-antigen lipopolysaccharide by an unknown mechanism. Wzz proteins consist of two transmembrane helices separated by a large periplasmic loop. The periplasmic loop of Escherichia coli K-12 Wzz (244 amino acids from K65 to A308) was purified and found to be a monomer with an extended conformation, as determined by gel filtration chromatography and analytical ultracentrifugation. Circular dichroism showed that the loop has a 60% helical content. The Wzz periplasmic loop also contains three regions with predicted coiled coils. To probe the function of the predicted coiled coils, we constructed amino acid replacement mutants of the E. coli K-12 Wzz protein, which were designed so that the coiled coils could be separate without compromising the helicity of the individual molecules. Mutations in one of the regions, spanning amino acids 108 to 130 (region I), were associated with a partial defect in O-antigen chain length distribution, while mutants with mutations in the region spanning amino acids 209 to 223 (region III) did not have an apparent functional defect. In contrast, mutations in the region spanning amino acids 153 to 173 (region II) eliminated the Wzz function. This phenotype was associated with protein instability, most likely due to conformational changes caused by the amino acid replacements, which was confirmed by limited trypsin proteolysis. Additional mutagenesis based on a three-dimensional model of region I demonstrated that the amino acids implicated in function are all located at the same face of a predicted alpha-helix, suggesting that a coiled coil actually does not exist in this region. Together, our results suggest that the regions predicted to be coiled coils are important for Wzz function because they maintain the native conformation of the protein, although the existence of coiled coils could not be demonstrated experimentally.

Genetic analysis of the O-specific lipopolysaccharide biosynthesis region (rfb) of Escherichia coli K-12 W3110:identification of genes that confer group 6 specificity to Shigella flexneri serotypes Y and 4a

We recently reported a novel genetic locus located in the sbcB-his region of the chromosomal map of Escherichia coli K-12 which directs the expression of group 6-positive phenotype in Shigella flexneri lipopolysaccharide, presumably due to the transfer of O-acetyl groups onto rhamnose residues of the S. flexneri O-specific polysaccharide (Z. Yao, H. Liu, and M. A. Valvano, J. Bacteriol. 174:7500-7508, 1992). In this study, we identified the genetic region encoding group 6 specificity as part of the rfb gene cluster of E. coli K-12 strain W3110 and established the DNA sequence of most of this cluster. The rfbBDACX block of genes, located in the upstream region of the rfb cluster, was found to be strongly conserved in comparison with the corresponding region in Shigella dysenteriae type 1 and Salmonella enterica. Six other genes, four of which were shown to be essential for the expression of group 6 reactivity in S. flexneri serotypes Y and 4a, were identified downstream of rfbX. One of the remaining two genes showed similarities with rfc (O-antigen polymerase) of S. enterica serovar typhimurium, whereas the other, located in the downstream end of the cluster next to gnd (gluconate-6-phosphate dehydrogenase), had an IS5 insertion. Recently, it has been reported that the IS5 insertion mutation (rfb-50) can be complemented, resulting in the formation of O16-specific polysaccharide by E. coli K-12 (D. Liu and P. R. Reeves, Microbiology 140:49-57, 1994). We present immunochemical evidence suggesting that S. flexneri rfb genes also complement the rfb-50 mutation; in the presence of rfb genes of E. coli K-12, S. flexneri isolates express O16-specific polysaccharide which is also acetylated in its rhamnose residues, thereby eliciting group 6 specificity.

Role of tol genes in cloacin DF13 susceptibility of Escherichia coli K-12 strains expressing the cloacin DF13-aerobactin receptor IutA

IutA is the outer membrane protein receptor for ferric aerobactin and the bacteriocin cloacin DF13. Although the same receptor is shared, ferric aerobactin transport across the outer membrane in Escherichia coli is TonB dependent, whereas cloacin DF13 transport is not. We have recently observed that tolQ is required for cloacin DF13 susceptibility (J.A. Thomas and M.A. Valvano, FEMS Microbiol. Lett. 91:107-112, 1992). In this study, we demonstrate that the genes tolQ, tolR, and tolA, but not tolB, tolC, and ompF, are required for the internalization of cloacin DF13 and they are not involved in the transport of ferric aerobactin.

Acetylation of O-specific lipopolysaccharides from Shigella flexneri 3a and 2a occurs in Escherichia coli K-12 carrying cloned S. flexneri 3a and 2a rfb genes

Most of the Shigella flexneri O-specific serotypes result from O-acetyl and/or glucosyl groups added to a common O-repeating unit of the lipopolysaccharide (LPS) molecule. The genes involved in acetylation and/or glucosylation of S. flexneri LPS are physically located on lysogenic bacteriophages, whereas the rfb cluster contains the biosynthesis genes for the common O-repeating unit (D.A.R. Simmons and E. Romanowska, J. Med. Microbiol. 23:289-302, 1987). Using a cosmid cloning strategy, we have cloned the rfb regions from S. flexneri 3a and 2a. Escherichia coli K-12 containing plasmids pYS1-5 (derived from S. flexneri 3a) and pEY5 (derived from S. flexneri 2a) expressed O-specific LPS which reacted immunologically with S. flexneri polyvalent O antiserum. However, O-specific LPS expressed in E. coli K-12 also reacted with group 6 antiserum, indicating the presence of O-acetyl groups attached to one of the rhamnose components of the O-repeating unit. This was confirmed by measuring the amounts of acetate released from purified LPS samples and also by the chemical removal of O-acetyl groups, which abolished group 6 reactivity. The O-acetylation phenotype was absent in an E. coli strain with an sbcB-his-rfb chromosomal deletion and could be restored upon conjugation of F' 129, which carries sequences corresponding to a portion of the deleted region. Our data demonstrate that E. coli K-12 strains possess a novel locus which directs the O acetylation of LPS and is located in the sbcB-rfb region of the chromosomal map.

Molecular cloning and expression in Escherichia coli K-12 of chromosomal genes determining the O7 lipopolysaccharide antigen of a human invasive strain of E. coli O7:K1

We have cloned and studied the expression in Escherichia coli K-12 of chromosomal rfb genes determining the biosynthesis of the O7 lipopolysaccharide (LPS) antigen from E. coli K1 strain VW187. Two E. coli K-12 strains carrying recombinant cosmids gave positive coagglutination reactions with protein A-rich staphylococcal particles bearing an O7-specific rabbit polyclonal antiserum. Silver-stained polyacrylamide gels of total membranes extracted with hot phenol showed O side chain material which had O7 specificity as determined by immunoblotting experiments. However, the amount of O7 LPS expressed in E. coli K-12 was considerably lower than that produced by the wild-type strain VW187. Deletion and transposition experiments identified a region of about 17 kilobase pairs which is essential for the expression of O7 LPS. The existence of homologies between the O7 LPS genes and other E. coli O side chain genes was investigated by Southern blot hybridization experiments. An O7-specific probe fragment of 15 kilobase pairs did not hybridize to genomic DNA digests of E. coli strains belonging to several different O types, demonstrating that the O7 LPS genes are unique.

Molecular cloning, expression, and regulation in Escherichia coli K-12 of a chromosome-mediated aerobactin iron transport system from a human invasive isolate of E. coli K1

We have cloned chromosomal genes determining the aerobactin iron transport system from the Escherichia coli K1 strain VW187. Mapping and hybridization experiments showed that the VW187 aerobactin region was identical to that of the plasmid ColV-K30. However, in the E. coli K-12 background, the biosynthesis of both siderophore and ferric aerobactin receptor encoded by the VW187-derived recombinant plasmids was not repressed by iron to the same extent found when a recombinant plasmid derived from pColV-K30 was used. RNA-DNA dot-blot hybridization experiments demonstrated that the aerobactin-specific mRNA synthesized by the VW187-derived clones was not iron regulated in E. coli K-12. In contrast, the synthesis of aerobactin and its receptor in strain VW187 was completely repressed by iron regardless of whether the recombinant plasmids originated from VW187 or pColV-K30. Similar results were obtained with gene fusions in which a promoterless lac operon was placed under the control of aerobactin promoter regions of either chromosome- or plasmid-mediated aerobactin systems. DNA sequencing of the chromosomal aerobactin promoter region showed changes in bases located immediately upstream to the -35 region compared with the corresponding region in pColV-K30, which is known to be part of the binding site for the Fur repressor protein.

EfeUOB (YcdNOB) is a tripartite, acid-induced and CpxAR-regulated, low-pH Fe2+ transporter that is cryptic in Escherichia coli K-12 but functional in E-coli O157 : H7

Escherichia coli possesses iron transporters specific for either Fe2+ or Fe3+. Although Fe2+ is far more soluble than Fe3+, it rapidly oxidizes aerobically at pH >= 7. Thus, FeoAB, the major Fe2+ transporter of E. coli, operates anaerobically. However, Fe2+ remains stable aerobically under acidic conditions, although a low-pH Fe2+ importer has not been previously identified. Here we show that ycdNOB (efeUOB) specifies the first such transporter. efeUOB is repressed at high pH by CpxAR, and is Fe2+-Fur repressed. EfeU is homologous to the high-affinity iron permease, Ftr1p, of Saccharomyces cerevisiae and other fungi. EfeO is periplasmic with a cupredoxin N-terminal domain; EfeB is also periplasmic and is haem peroxidase-like. All three Efe proteins are required for Efe function. The efeU gene of E. coli K-12 is cryptic due to a frameshift mutation - repair of the single-base-pair deletion generates a functional EfeUOB system. In contrast, the efeUOB operon of the enterohaemorrhagic strain, O157:1147, lacks any frameshift and is functional. A 'wild-type' K-12 strain bearing a functional EfeUOB displays a major growth advantage under aerobic, low-pH, low-iron conditions when a competing metal is provided. Fe-55 transport assays confirm the ferrous iron specificity of EfeUOB.