In Situ Monitoring and Quantitative Determination of R27 Plasmid Conjugation.

Horizontal gene transfer (HGT) by plasmid conjugation is a major driving force in the spread of antibiotic resistance among Enterobacteriaceae. Most of the conjugation studies are based on calculation of conjugation ratios (number of transconjugants/number of donors) after viable counting of transconjugant and donor cells. The development of robust, fast and reliable techniques for in situ monitoring and quantification of conjugation ratios might accelerate progress in understanding the impact of this cellular process in the HGT. The IncHI1 plasmids, involved in multiresistance phenotypes of relevant pathogens such as Salmonella and E. coli, are distinguished by the thermosensitivity of their conjugative transfer. Conjugation mediated by IncHI1 plasmids is more efficient at temperatures lower than 30 °C, suggesting that the transfer process takes place during the environmental transit of the bacteria. In this report, we described a methodology to monitor in situ the conjugation process during agar surface matings of the IncHI1 plasmid R27 and its derepressed derivative drR27 at different temperatures. A three-color-labeling strategy was used to visualize the spatial distribution of transconjugants within the heterogeneous environment by epifluorescence and confocal microscopy. Moreover, the fluorescent labelling was also used to quantify conjugation frequencies in liquid media by flow cytometry.

Temperature Dependent Control of the R27 Conjugative Plasmid Genes.

Conjugation of R27 plasmid is thermoregulated, being promoted at 25°C and repressed at 37°C. Previous studies identified plasmid-encoded regulators, HtdA, TrhR and TrhY, that control expression of conjugation-related genes (tra). Moreover, the nucleoid-associated protein H-NS represses conjugation at non-permissive temperature. A transcriptomic approach has been used to characterize the effect of temperature on the expression of the 205 R27 genes. Many of the 35 tra genes, directly involved in plasmid-conjugation, were upregulated at 25°C. However, the majority of the non-tra R27 genes-many of them with unknown function-were more actively expressed at 37°C. The role of HtdA, a regulator that causes repression of the R27 conjugation by counteracting TrhR/TrhY mediated activation of tra genes, has been investigated. Most of the R27 genes are severely derepressed at 25°C in an htdA mutant, suggesting that HtdA is involved also in the repression of R27 genes other than the tra genes. Interestingly, the effect of htdA mutation was abolished at non-permissive temperature, indicating that the HtdA-TrhR/TrhY regulatory circuit mediates the environmental regulation of R27 gene expression. The role of H-NS in the proposed model is discussed.

A characterization of finite abelian groups via sets of lengths in transfer Krull monoids.

Let H be a transfer Krull monoid over a finite abelian group G (for example, rings of integers, holomorphy rings in algebraic function fields, and regular congruence monoids in these domains). Then each nonunit a∈H can be written as a product of irreducible elements, say a=u1…uk , and the number of factors k is called the length of the factorization. The set L(a) of all possible factorization lengths is the set of lengths of a. It is classical that the system ℒ(H) = {L(a)∣a∈H} of all sets of lengths depends only on the group G, and a standing conjecture states that conversely the system ℒ(H) is characteristic for the group G. Let H' be a further transfer Krull monoid over a finite abelian group G' and suppose that ℒ(H) = â„’(H' ). We prove that, if G≅Cnr with r≤n-3 or (r≥n-1≥2 and n is a prime power), then G and G' are isomorphic.

SHAPE BASED IMAGE RECONSTRUCTION USING LINEARIZED DEFORMATIONS.

We introduce a reconstruction framework that can account for shape related a priori information in ill-posed linear inverse problems in imaging. It is a variational scheme that uses a shape functional defined using deformable templates machinery from shape theory. As proof of concept, we apply the proposed shape based reconstruction to 2D tomography with very sparse measurements, and demonstrate strong empirical results.

Sensitization of glycoengineered interferon-ß1a-resistant cancer cells by cFLIP inhibition for enhanced anti-cancer therapy.

In this study, we examined the molecular mechanism underlying the resistance of cancer cells to R27T, a glycoengineered version of recombinant human interferon (IFN)-ß1a, and sought to overcome R27T resistance through combination therapy. R27T has been shown to induce anti-proliferation and apoptosis in human OVCAR-3 and MCF-7 cells, but not in HeLa cells. R27T treatment increased caspase-8 activity and the consequent cleavage of caspase-8 and -3 in R27T-sensitive OVCAR-3 cells, but not in R27T-resistant HeLa cells. Conversely, R27T increased the expression of cellular FLICE-like inhibitory protein (cFLIP) in HeLa cells, but not in OVCAR-3 cells. The sensitization of HeLa cells with cFLIP small interfering RNA or 4,5,6,7-tetrabromobenzotriazole (TBB, an inhibitor of casein kinase-2) facilitated R27T-induced caspase activation, and consequently apoptosis. In OVCAR-3-xenografted mice, intraperitoneal administration of R27T showed 2.1-fold higher anti-tumor efficacy than did the control vehicle. The combined administration of R27T and TBB showed the greatest anti-tumor effect in HeLa tumor-bearing mice, reducing the relative tumor volume by 35.7% compared to that in R27T-treated mice. Taken together, our results suggest that R27T has potential as an anti-cancer drug, and combination therapy with cFLIP inhibitors may be an effective strategy for overcoming R27T resistance.

The incC Sequence Is Required for R27 Plasmid Stability.

IncHI plasmids account for multiple antimicrobial resistance in Salmonella and other enterobacterial genera. These plasmids are generally very stable in their bacterial hosts. R27 is the archetype of IncHI1 plasmids. A high percentage of the R27-encoded open reading frames (ORFs) (66.7%) do not show similarity to any known ORFs. We performed a deletion analysis of all non-essential R27 DNA sequences to search for hitherto non-identified plasmid functions that might be required for plasmid stability. We report the identification of a short DNA sequence (incC) that is essential for R27 stability. That region contains several repeats (incC repeats), belongs to one of the three-plasmid replicons (R27 FIA-like) and is targeted by the R27 E protein. Deletion of the incC sequence drastically reduces R27 stability both in Escherichia coli and in Salmonella, the effect being more pronounced in this latter species. Interfering with incC-E protein interaction must lead to a reduced IncHI1 plasmid stability, and may represent a new approach to combat antimicrobial resistance.

Validação brasileira do teste não-verbal de inteligência SON-R 2½-7[a] / Brazilian validation of the nonverbal intelligence test SON-R 2½-7[a] / Validación brasileña de la prueba no verbal de inteligencia SON-R 2½-7[a]

Este artigo apresenta estudos realizados no Brasil referentes à evidência de validade de construto do teste SON-R 2½-7[a], versão abreviada do SON-R 2½-7, que possui estudos de normatização e validação realizados em vários países europeus. O SON-R 2½-7[a] é um instrumento não-verbal que avalia amplas áreas de inteligência para crianças entre 2½ e 7 anos. Os dados da amostra nacional de normatização brasileira com 1.200 crianças foram analisados utilizando tanto análise fatorial exploratória como análise fatorial confirmatória. Os resultados apóiam a distinção adotada no teste entre a escala de execução e a escala de raciocínio. Os resultados indicam uma boa validade de construto do SON-R 2½-7[a] e sugerem que o teste é uma ferramenta promissora para a avaliação das habilidades cognitivas de crianças no Brasil.

This article presents studies realized in Brazil related to evidence of the construct validity of the SON-R 2½-7[a], the abridged edition of the SON-R 2½-7, a nonverbal test with normatization and validation studies realized in various European countries. The SON-R 2½-7[a] measures broad areas of intelligence for children between 2½ and 7 years of age. Data of a national sample of 1,200 children of the normatization study in Brazil were analyzed, using both exploratory and confirmatory factor analysis. The results support the distinction adopted in the test between a performance and a reasoning scale. The findings indicate a good construct validity of the SON-R 2½-7[a] and suggest that it is a promising tool for the evaluation of cognitive abilities of young children in Brazil.

Este artículo presenta estudios realizados en Brasil relacionados con las evidencias de validez de constructo del test SON-R 2½-7[a], una versión abreviada del SON-R 2½ -7 que tiene estudios de estandarización y validación realizados en varios países europeos. El SON-R 2½-7[a] es un instrumento no verbal que evalúa áreas amplias de inteligencia para niños entre 2½ y 7 años. Los datos de la muestra nacional de normalización de 1.200 niños brasileños se analizaron mediante análisis factorial exploratorio y el análisis factorial confirmatorio. Los resultados apoyan la distinción adoptada para la prueba entre la escala de ejecución y la escala de razonamiento. Los resultados indican una buena validez de constructo del SON-R 2½ -7[a] y sugieren que la prueba es una herramienta prometedora para la evaluación de las capacidades cognitivas de los niños en Brasil.

Validação brasileira do teste não-verbal de inteligência SON-R 2½-7[a] / Brazilian validation of the nonverbal intelligence test SON-R 2½-7[a]

Este artigo apresenta estudos realizados no Brasil referentes à evidência de validade de construto do teste SON-R 2½-7[a], versão abreviada do SON-R 2½-7, que possui estudos de normatização e validação realizados em vários países europeus. O SON-R 2½-7[a] é um instrumento não-verbal que avalia amplas áreas de inteligência para crianças entre 2½ e 7 anos. Os dados da amostra nacional de normatização brasileira com 1.200 crianças foram analisados utilizando tanto análise fatorial exploratória como análise fatorial confirmatória. Os resultados apóiam a distinção adotada no teste entre a escala de execução e a escala de raciocínio. Os resultados indicam uma boa validade de construto do SON-R 2½-7[a] e sugerem que o teste é uma ferramenta promissora para a avaliação das habilidades cognitivas de crianças no Brasil.(AU)

This article presents studies realized in Brazil related to evidence of the construct validity of the SON-R 2½-7[a], the abridged edition of the SON-R 2½-7, a nonverbal test with normatization and validation studies realized in various European countries. The SON-R 2½-7[a] measures broad areas of intelligence for children between 2½ and 7 years of age. Data of a national sample of 1,200 children of the normatization study in Brazil were analyzed, using both exploratory and confirmatory factor analysis. The results support the distinction adopted in the test between a performance and a reasoning scale. The findings indicate a good construct validity of the SON-R 2½-7[a] and suggest that it is a promising tool for the evaluation of cognitive abilities of young children in Brazil.(AU)

Este artículo presenta estudios realizados en Brasil relacionados con las evidencias de validez de constructo del test SON-R 2½-7[a], una versión abreviada del SON-R 2½ -7 que tiene estudios de estandarización y validación realizados en varios países europeos. El SON-R 2½-7[a] es un instrumento no verbal que evalúa áreas amplias de inteligencia para niños entre 2½ y 7 años. Los datos de la muestra nacional de normalización de 1.200 niños brasileños se analizaron mediante análisis factorial exploratorio y el análisis factorial confirmatorio. Los resultados apoyan la distinción adoptada para la prueba entre la escala de ejecución y la escala de razonamiento. Los resultados indican una buena validez de constructo del SON-R 2½ -7[a] y sugieren que la prueba es una herramienta prometedora para la evaluación de las capacidades cognitivas de los niños en Brasil.(AU)

Funcionamento diferencial dos itens do teste não-verbal de inteligência SON-R 2½-7[a] / Differential item functioning of the SON-R 2½-7[a] non-verbal intelligence test

A presença de uma quantidade considerável de itens com funcionamento diferencial (DIF) pode tornar um teste menos válido. Assim, este estudo investigou a existência de DIF no teste de inteligência SON-R 2½-7[a]. O teste é a versão abreviada do SON-R 2½-7, normatizado e validado em vários países da Europa. Os dados de 1.200 crianças da normatização brasileira foram utilizados para identificar a presença de DIF em relação à gênero e região, usando o método da TRI. Os resultados indicaram que, de um total de 60 itens, 5 itens apresentaram DIF entre os sexos e 13 itens apresentaram DIF entre as regiões. Conclui-se que há adequabilidade da maioria dos itens, o que viabiliza o uso do SON-R 2½-7[a] em contexto nacional.

The presence of a considerable amount of items with differential functioning can make a test less valid. Therefore, the existence of Differential Item Functioning (DIF) in the intelligence test SON-R 2½-7[a] was investigated. This is the abridged edition of the SON-R 2½-7 with normatization and validation studies realized in various European countries. The data of the Brazilian normatization sample of 1,200 children were used to verify the presence of DIF in relation to gender and region using the IRT method. Of a total of 60 items, 5 items were indicated as having DIF for gender and 13 items as having DIF between regions. It was concluded that the majority of the items were adequate, which makes the use of the test feasible in a national context.

Funcionamento diferencial dos itens do teste não-verbal de inteligência SON-R 2½-7[a] / Differential item functioning of the SON-R 2½-7[a] non-verbal intelligence test

A presença de uma quantidade considerável de itens com funcionamento diferencial (DIF) pode tornar um teste menos válido. Assim, este estudo investigou a existência de DIF no teste de inteligência SON-R 2½-7[a]. O teste é a versão abreviada do SON-R 2½-7, normatizado e validado em vários países da Europa. Os dados de 1.200 crianças da normatização brasileira foram utilizados para identificar a presença de DIF em relação à gênero e região, usando o método da TRI. Os resultados indicaram que, de um total de 60 itens, 5 itens apresentaram DIF entre os sexos e 13 itens apresentaram DIF entre as regiões. Conclui-se que há adequabilidade da maioria dos itens, o que viabiliza o uso do SON-R 2½-7[a] em contexto nacional.(AU)

The presence of a considerable amount of items with differential functioning can make a test less valid. Therefore, the existence of Differential Item Functioning (DIF) in the intelligence test SON-R 2½-7[a] was investigated. This is the abridged edition of the SON-R 2½-7 with normatization and validation studies realized in various European countries. The data of the Brazilian normatization sample of 1,200 children were used to verify the presence of DIF in relation to gender and region using the IRT method. Of a total of 60 items, 5 items were indicated as having DIF for gender and 13 items as having DIF between regions. It was concluded that the majority of the items were adequate, which makes the use of the test feasible in a national context.(AU)

Indicações da validade convergente do teste Não-Verbal de Inteligência Son-R 2½-7[A] / Indications of the convergent validaty of the Non-verbal Tes of Intelligence Son-R 2½-7[A]

O objetivo deste estudo foi avaliar a validade convergente do teste não-verbal de inteligência SON-R 2½-7[a] no Brasil. O teste em questão é a versão abreviada do SON-R 2½-7 que foi publicado na Holanda em 1998 e que foi normatizado e validado em vários países de Europa. A versão abreviada foi administrada no Brasil em 120 crianças com idade variando entre 5 e 7 anos junto com as Matrizes Progressivas Coloridas (MPC) do Raven e com a Escala de Maturidade Mental Colúmbia (EMMC). A correlação, corrigida para atenuação, do SON-R 2½-7[a] com estes dois testes foi respectivamente, 0,77, e 0,62. Foi observada uma relação particularmente forte entre o MPC e a escala de execução do SON-R 2½-7[a], e entre o EMMC e a escala de raciocínio do SON-R 2½-7[a]. Os resultados do presente estudo indicam uma boa validade convergente do teste para a faixa de idade investigada.

This study aimed to investigate the convergent validity of the nonverbal test of intelligence SON-R 2½-7[a] in Brazil. This test is the abridged edition of the SON-R 2½-7 nonverbal test of intelligence that was published in 1998 in The Netherlands with normatization and validation studies realized in various European countries. The abridged edition was administered in Brazil to 120 children with ages varying between 5 and 7 years together with Raven’s Colored Progressive Matrices (CPM) and the Columbia Mental Maturity Scale (EMMC). The correlation, corrected for attenuation, of the SON-R 2½-7[a] with these two tests was .77 and .62, respectively. A particularly strong relationship was observed between the CPM and the performance scale of the SON-R 2½-7[a], and between the EMMC and the SON-R reasoning scale. The results of this study indicate a fair convergent validity of the SON-R 2½-7[a] for the investigated age group.

Indicações da validade convergente do teste Não-Verbal de Inteligência Son-R 2½-7[A] / Indications of the convergent validity of the non-verbal test of intelligence Son-R 2½-7[A]

O objetivo deste estudo foi avaliar a validade convergente do teste não-verbal de inteligência SON-R 2½-7[a] no Brasil. O teste em questão é a versão abreviada do SON-R 2½-7 que foi publicado na Holanda em 1998 e que foi normatizado e validado em vários países de Europa. A versão abreviada foi administrada no Brasil em 120 crianças com idade variando entre 5 e 7 anos junto com as Matrizes Progressivas Coloridas (MPC) do Raven e com a Escala de Maturidade Mental Colúmbia (EMMC). A correlação, corrigida para atenuação, do SON-R 2½-7[a] com estes dois testes foi respectivamente, 0,77, e 0,62. Foi observada uma relação particularmente forte entre o MPC e a escala de execução do SON-R 2½-7[a], e entre o EMMC e a escala de raciocínio do SON-R 2½-7[a]. Os resultados do presente estudo indicam uma boa validade convergente do teste para a faixa de idade investigada.(AU)

This study aimed to investigate the convergent validity of the nonverbal test of intelligence SON-R 2½-7[a] in Brazil. This test is the abridged edition of the SON-R 2½-7 nonverbal test of intelligence that was published in 1998 in The Netherlands with normatization and validation studies realized in various European countries. The abridged edition was administered in Brazil to 120 children with ages varying between 5 and 7 years together with Raven's Colored Progressive Matrices (CPM) and the Columbia Mental Maturity Scale (EMMC). The correlation, corrected for attenuation, of the SON-R 2½-7[a] with these two tests was .77 and .62, respectively. A particularly strong relationship was observed between the CPM and the performance scale of the SON-R 2½-7[a], and between the EMMC and the SON-R reasoning scale. The results of this study indicate a fair convergent validity of the SON-R 2½-7[a] for the investigated age group.(AU)