272 research outputs found
Guia do arquivo pessoal de Helios Seelinger
No full textGuia descritivo do Arquivo pessoal de Helios Aristides Seelinger (Rio de Janeiro, RJ 1878 - Rio de Janeiro, RJ 1965), realizado no âmbito da pesquisa de doutorado de João Victor Rossetti Brancato no Programa de Pós-Graduação em História da Universidade Estadual de Campinas (UNICAMP) entre 2019 e 2025, sob orientação do Prof. Jorge Coli e financiamento da pesquisa pela Fundação de Amparo à Pesquisa do Estado de São Paulo (Processo nº 19/08063-8). A realização do Guia contou com o apoio de Heloisa Maria Seelinger Pereira da Silva, guardiã do arquivo do artista.
Em 2020, parte dos documentos do arquivo foram doados ao Centro de Documentação e Memória da Pinacoteca do Estado de São Paulo, constituindo o Fundo Helios Seelinger (BR SPPSP HS), composto por 339 itens identificados pelo intervalo de notação HS.00001 a HS.00339 e disponível online em: http://biblioteca.pinacoteca.org.br:9090/site/php/index.php. No Guia a seguir, produzido entre 2019 e 2020 e atualizado em 2025, são descritos sumariamente todos os itens localizados no arquivo antes da doação
Characterization of Escherichia coli strains carrying different rpos alleles.
No full textA bactéria Escherichia coli é encontrada em diversos habitats e deve estar preparada para sobreviver e crescer em condições desfavoráveis. A adaptação da bactéria a diferentes condições obriga-a a controlar a expressão de genes de forma eficiente. Uma das formas primárias de controle de expressão gênica é a competição entre os diversos fatores sigma pela ligação ao cerne da RNA polimerase. <font face=\"Symbol\">d70 é o fator sigma mais abundante e participa da transcrição da maioria dos genes de E. coli, enquanto que <font face=\"Symbol\">dS é o segundo em importância e reconhece promotores de genes relacionados à resposta geral ao estresse. O gene rpoS, que codifica para <font face=\"Symbol\">dS é altamente polimórfico, e adquiri mutações frequentemente. A mutação pontual C<font face=\"Symbol\">®T na posição 97 da ORF de rpoS, resulta em um códon de parada TAG (âmbar). Um Shine-Dalgarno alternativo e um códon de início de tradução na posição 157 dá início a uma proteína RpoS truncada, que é parcialmente funcional. Uma das situações de estresse na qual <font face=\"Symbol\">dS é ativado corresponde à privação de fosfato inorgânico. Porém, na limitação deste nutriente ocorre também a ativação do regulon PHO, cujos genes são predominantemente transcritos por <font face=\"Symbol\">d70. Neste trabalho, o efeito da versão truncada de RpoS sobre a expressão de genes dependentes de <font face=\"Symbol\">d70 (lacZ, phoA e pstS) e de genes dependentes de <font face=\"Symbol\">dS (osmY e proU) foi testado. Foram também realizados ensaios de estresse oxidativo, osmótico e pelo frio. O perfil de atividade parcial descrito para RpoSam pôde ser observado em alguns casos, porém em outros o comportamento deste alelo se assemelhou ao do mutante rpoS nulo. Paralelamente, foi testada também uma cepa de E. coli que carrega a mutação âmbar em rpoS, mas esta é suprimida, resultando na expressão de uma proteína RpoS normal. A proteína RpoS truncada não pôde ser visualizada em immunoblots, provavelmente porque esta é traduzida de forma pouco eficiente a partir do Shine-Dalgarno alternativo. Com o objetivo de incrementar a detecção de RpoS em ensaios de imuno-detecção, foi inserida por recombinação alélica uma etiqueta SPA altamente imunogênica na porção C-terminal da proteína.Escherichia coli can be found in many different habitats and has to be prepared to survive and grow under unfavorable conditions. Bacteria adaptation to different growth conditions requires an efficient control of gene expression. One of the primary forms of gene expression control is the competition between different sigma factors for the binding to the core RNA polymerase. <font face=\"Symbol\">d70 is the most abundant sigma factor and participates in the transcription of most E. coli genes. <font face=\"Symbol\">dS is the second one in importance and recognizes promoters of genes related to the general stress response. The rpoS gene, which encodes <font face=\"Symbol\">dS, is highly polymorphic and acquires mutations very often. The transition C<font face=\"Symbol\">®T at position 97 in the rpoS ORF results in a stop codon TAG (amber). Due to the presence of an alternative Shine-Dalgarno and a translation initiation codon at position 157 a truncated RpoS protein that is partially functional is translated. One of the stress situations that <font face=\"Symbol\">dS is activated is the starvation for inorganic phosphate. Phosphate limitation also triggers the activation of the PHO regulon, whose genes are predominantly transcribed by <font face=\"Symbol\">d70. In the present study, the effect of the truncated version of RpoS on the expression of <font face=\"Symbol\">d70 dependent genes (lacZ, phoA e pstS) and <font face=\"Symbol\">dS dependent genes (osmY e proU) was tested. Bacteria were also assayed for sensitivity to oxidative, osmotic and cold stress. The profile of partial activity described for the truncated RpoS could be observed in some cases, while in others the behavior of this allele resembled the rpoS null mutant. In parallel, an E. coli strain which suppresses the amber mutation in RpoS, resulting in the expression of a normal protein was also tested. A band correponding to the truncated RpoS could not be detected in immunoblots probably due to inefficient translation from the alternative Shine-Dalgarno. To improve the detection of RpoS, a highly immunogenic SPA tag was inserted in the C-terminal region of the protein
De buena madera: Trabajos de Heloisa Crocco
No full textHeloisa Crocco developed her artistic talent by being surrounded by the green of the jungle nature, perceiving this enormous garden as the binomial Art-Nature translated as an exaltation of life. In 2010, with more than thirty years of experience, the Brazilian designer brought out her book Topomorfose, which brings together the results of an exhaustive research carried out throughout her career. The protagonist of the text is wood. The book is accompanied by thoughts and concepts as well as poems by Juan Alberto Nemer and photos by Fabio del Re, VivaFoto and Carlos Stein. Topomorfose becomes, page by page, her philosophy and the author\u27s understanding of herself and the world, as well as showing her experience that in some way defines her life\u27s quest.Heloisa Crocco desarrolló su talento artístico al estar rodeada del verde de la naturaleza selvática, percibiendo este enorme jardín como el binomio Arte-Naturaleza traducido como una exaltación de la vida. En el año 2010, con más de treinta años de trayectoria, la diseñadora brasileña, saca a la luz su libro Topomorfose, el cual reúne los resultados de una investigación realizada exhaustivamente a lo largo de su carrera. La protagonista del texto es la madera. El libro viene de la mano de pensamientos y conceptos además de incluir poemas de Juan Alberto Nemer y fotos de Fabio del Re, VivaFoto y Carlos Stein. Topomorfose se convierte, página a página, en su filosofía y en la comprensión que la autora tiene tanto de sí misma como del mundo, además de mostrar su experiencia que de alguna manera definiría la búsqueda de su vida
Characterization of traditional kefir on physicalchemical composition, sensorial characteristic and anti-Escherichia coli activity
No full textKefir é um alimento fermentado resultante da dupla fermentação do leite pelos grãos de kefir, sendo estes grãos uma associação simbiótica de leveduras, bactérias ácido-láticas e bactérias ácido-acéticas. Do kefir pode-se obter o kefir leban e o soro de kefir, ambos resultantes da filtração do kefir em tecido de algodão esterilizado, por 24 horas, a 25ºC ± 2ºC. Este estudo tem por objetivos caracterizar e avaliar o comportamento de diferentes amostras de grãos de kefir tradicional e de derivados (kefir, kefir leban e soro de kefir) quanto às características físico-químicas, sensoriais, intenção de compra e atividade anti-Escherichia coli, quando inoculados em diferentes concentrações, padronizando-se o tipo de leite, o tempo e a temperatura de incubação, a maturação e a filtração. Foram desenvolvidas análises fisicoquímicas, a avaliação sensorial através do teste de aceitabilidade e preferência e a determinação de atividade anti-Escherichia coli. Os resultados demonstraram que a técnica de manipulação e padronização das amostras foi eficaz na obtenção de produtos com características idênticas, visto a reprodutibilidade dos resultados. Também indicam que o volume de leite utilizado na incubação influencia significativamente nas características do produto final. O kefir leban obtido do experimento apresentou consistência cremosa, semelhante ao queijo quark, aroma característico de laticínio fermentado, cor amarela esbranquiçada, sabor ácido e boa espalhabilidade. Manteve os teores de cálcio contidos no leite após o processamento, concentrou as proteínas e gorduras, além de não conter lactose. Apresentou boa aceitabilidade e 58% de intenção de compra, quando utilizado na elaboração de formulações alimentares tipo antepasto. O kefir e o soro de kefir apresentaram Intensidade de Atividade de Inibição Bacteriana/bacteriostasia e Intensidade de Atividade de Inativação Bacteriana/ bactericidia máximas frente ao inóculo bacteriano Escherichia coli (ATCC 11229), testado em concentrações <=108 UFC/mL.Kefir is a fermented food resulting from the double fermentation of milk by kefir grains, these grains are a symbiotic association of yeasts, acid-lactic and acetic-acid bacteria. From kefir can be obtained kefir leban and kefir whey, both from the filtration of kefir in sterile cotton cloth, during 24 hours at 25°C ± 2ºC. This study aims to characterize and evaluate the behavior of different samples of traditional kefir grains and products derived (kefir, kefir leban and kefir whey) on the physicochemical composition, sensorial characteristic, intent to buy and anti-Escherichia coli activity, when inoculated in different concentrations, standardized the type of milk, the time and temperature of incubation, the maturation and filtration processes. Were developed physical and chemical analysis, the sensory evaluation using the tests of acceptability and preference and determination of anti-Escherichia coli activity. The results showed that the technique of handling and standardizing of the samples was effective in providing products with similar characteristics as the reproductibility of results. It is also indicate that the volume of milk used in the incubation influence significantly the characteristics of the final product. The kefir leban obtained in the experiment showed creamy consistency, similar to quark cheese, characteristic aroma of fermented dairy, whitish yellow color, acid flavor and good spread. He maintained the calcium contained in milk after processing,he concentrated protein, and don't contain any lactose. The product showed good acceptability and 58% of purchase intention, when used in the preparation of food formulations such hors d'oeuvre. The kefir and the kefir whey showed maximal intensity of bacterial inhibition activity/bacteriostasys, and intensity of bacterial inactivation activity/bactericidie in front of inoculum of Escherichia coli (ATCC 11229), tested at concentrations <=108CFU/mL
Dinâmica proteômica de Escherichia coli em resposta à limitação de nitrogênio
No full textOrientador: Prof. Dr. Luciano F. Huergo.Coorientadores: Prof. Dr. Glaucio Valdameri, Drª Edileusa C. M. Gerhardt.Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Ciências Bioquímica. Defesa : Curitiba, 19/08/19.Inclui referências: p. 82-97.Resumo: O nitrogênio é um elemento necessário para a biossíntese de diversas biomoléculas, incluindo proteínas e ácidos nucléicos. Na ausência de nitrogênio, procariotos como Escherichia coli cessam imediatamente o crescimento. Amônio é a fonte de nitrogênio de preferência para E. coli e confere as maiores taxas de crescimento. Sob condições de limitação de amônio, E. coli é capaz de utilizar fontes alternativas de nitrogênio, sendo que esta reprogramação é conduzida através da indução do regulon NtrC. Neste trabalho foi utilizada a técnica de proteômica livre de marcação para determinar a dinâmica da expressão de proteínas de E. coli em resposta à privação de nitrogênio, tanto inicialmente (30 min) quanto tardiamente (60 min). A abundância de proteínas e modificações pós-traducionais confirmaram que a ativação do regulon NtrC atua como a primeira linha de defesa da célula contra a falta de nitrogênio. A poteína Rmf (ribosome modulation fator) foi induzida logo após a célula ser submetida à privação de amônio, seguido da expressão de outras proteínas que atuam inativando os ribossomos, como Hpf e RaiA, apoiando a hipótese de que a inativação dos ribossomos é um processo importante durante a limitação de nitrogênio. O promotor rmf foi estudado e contém um promotor sigma54 além do sítio de ligação sigma70. Os dados proteômicos revelaram que a parada do crescimento devido à falta de nitrogênio se correlaciona com o acúmulo de proteínas envolvidas na condensação do DNA, no catabolismo de RNA e proteína e com hibernação de ribossomo. Coletivamente, essas adaptações proteômicas resultam em células metabolicamente inativas que possivelmente exibem tolerância a múltiplas drogas.Abstract: Nitrogen is needed for the biosynthesis of biomolecules including proteins and nucleic acids. In the absence of fixed nitrogen, prokaryotes such as E. coli immediately ceases growth. Ammonium is the preferred nitrogen source for E. coli supporting the fastest growth rates. Under conditions of ammonium limitation, E. coli can use alternative nitrogen sources and this reprogramming is orchestrated by the induction of the NtrC regulon. We use label free proteomics to determine the dynamics of E. coli proteins expression in response to nitrogen starvation after both short (30 min) and long (60 min) term. Protein abundances and post-translational modifications confirmed that activation of the NtrC regulon acts as the first line of defense against nitrogen starvation. The ribosome inactivating protein Rmf was induced shortly after ammonium exhaustion and this was followed by induction of other ribosome inactivating proteins such as Hpf and RaiA. These data support the hypothesis that ribosome shut-down is a key process during nitrogen limitation stress. The rmf promoter was studied and it contains a sigma54 promoter in addition to the sigma70 binding site. The proteomic data revealed that growth arrest due to nitrogen starvation correlates with the accumulation of proteins involved in DNA condensation, RNA and protein catabolism and ribosome hibernation. Collectively, these proteome adaptations will result in metabolic inactive cells which are likely to exhibit multidrug tolerance
n. 45 - JUDICIALIZAÇÃO DA EDUCAÇÃO INFANTIL: TRAJETÓRIAS E EFEITOS EM UM CASO PIONEIRO
No full textO artigo se insere na literatura sobre a judicialização de políticas públicas de educação infantil, analisando especificamente o caso de Santo André (SP), município que propôs no Supremo Tribunal Federal (STF) os Recursos Extraordinários que viriam a provocar, em 2005 e 2006, as primeiras decisões do Tribunal no sentido de reconhecer a educação infantil não-obrigatória como prerrogativa constitucional indisponível das crianças e de seus pais e responsáveis, afirmando assim a exigibilidade desse direito. A pesquisa compreende o período de 2006 a 2018 e exigiu análise de dados, documentos e entrevistas. Na interpretação dos resultados tomamos como base a metodologia de identificação de efeitos desenvolvida por Silveira et al (2020), adaptando-a à realidade encontrada no Município, no qual prevaleceu, até 2017, a judicialização pela via de demandas judiciais individuais e repetitivas, voltadas à obtenção de liminares individuais para a determinação de matrículas de crianças arroladas nas ações, padrão decisório mais disseminado, segundo a literatura analisada. Encontramos efeitos diretos da judicialização na política educacional, na administração pública e no sistema de justiça; e efeitos indiretos em quatro dimensões. Destacaram-se como efeitos a ampliação do atendimento da rede municipal, a superlotação de creches, a piora nas condições de qualidade da educação e a mudança do padrão decisório, identificada como efeito indireto do esgotamento do modelo de judicialização anterior
Enhancing Courses with Video Interviews - DE Oracle
No full textDE Oracle @ UMUC
An Online Learning Magazine for UMUC Faculty
Center for Support of Instruction
Enhancing Courses with Video Interviews
Heloisa Siffert
Senior Instructional Support Specialist
Center for Support of Instruction
Published: January-February 2008
Category: » Online-pedagogy » Teaching-strategies
Video interviews can enhance learning process, engage
students and provide real life experiences through experts'
perspectives.
During the span of two years, a series of video interviews were
developed for TMAN 636, Knowledge Management (KM). The
instructor, Dr. Flavia Fonseca, capitalized on her personal
contacts in the knowledge management field to arrange
interviews with professionals in the area. Dr. Fonseca facilitated
several interviews that took place at the interviewees' office
location. Heloisa Siffert, a staff member from the Center for
Support of Instruction (CSI), assisted with the recording, editing and publishing of interviews to Dr.
Fonseca's classroom.
The key idea for conducting the video interviews was to provide students with concrete descriptions of
various KM practitioners' experiences in order to complement class discussions and written case
studies. The main advantage was to show what worked and what didn't in these KM implementations.
The World Bank case exemplifies this approach with two different facets being presented: Information
Technology through the vision of the CIO (Chief Information Officer) and Knowledge Management
through the view of its CKO (Chief Knowledge Officer).
Another important aspect of the interview series was to bring new KM topics that are currently in
development. For example, Dr. Blair, the author of several books and studies on KM, was invited to talk
about new approaches that are still being tested, such as Personal Knowledge Management. The video
interview was used in combination with the author participation as a guest speaker in the classroom.
Mr. Kahan was invited to discuss some specific tools and methods that are particularly important to KM
programs. In his interview, Mr. Kahan brought his views about development of Communities of
Practice.
From the production aspect, the video interviews were low cost but had a high impact result. Each
video was recorded, edited, transcribed and ultimately published as a webpage. The page served as a
package for that respective interview, and included information about the speaker and relevant support
references.
Students' feedback was extremely positive to all videos. Particularly successful was the video of the
World Bank Case where different scenarios were represented with more than one interviewee. The
students appreciated the fact that they could see the interviewees, which helped to break the
text-based routine of the online classroom, as well as the ability to submit questions that were used to
guide the interviews.
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The lesson learned from this experience suggests that it was relatively easy to produce a project with a
high impact on the course. However, close involvement from both the faculty and the CSI staff member
was essential to the development of the multimedia objects.
The method is relatively simple to replicate for other courses such as foreign language, biotechnology,
etc. The video object can easily evolve into a "learning object" by associating it to other web links and
documents, which support a subject discussed in an interview. Video interviewing is ideal for enhancing
educational experiences, particularly in those subjects where there are limited multimedia resources to
supplement instruction.
About the Author(s)
Heloisa Siffert Senior Instructional Support Specialist, Center for Support of Instruction, develops and delivers faculty training
programs, and collaborates with the academic units on online classroom setup, course design, learning objects development
and implementations of new technologies. Her areas of expertise include graphic design and web/multimedia development.
Flavia Fonseca Adjunct Associate Professor at UMUC since 2005. Extensive Knowledge Management consulting experience
around the world, Brazil, Africa and Asia. In the USA, she was Chief Information Architect and Manager, at the World Bank
until 2001. There she accumulated a substantial experience in managing large projects and also helped to develop, since its
beginning, a very comprehensive program in Knowledge Management which is considered by many as a model in this area.
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Atividade antibacteriana "in vitro" de diferentes acessos de urucum (Bixa orellana L.) e sua relação com o teor de bixina presente nas sementes.
No full textEste trabalho teve como objetivo avaliar a atividade bacteriostática/inibição e bactericida/inativação "in vitro" de extratos hidroetanólicos e hídricos (decoctos e infusos), obtidos de diferentes acessos de sementes de B. orellana L. (urucum) originários dos municípios de Arroio do Meio (RS), Eldorado do Sul (RS) e Maringá (PR) frente a agentes bacterianos padrões internacionais de interesse de alimentos, respectivamente Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis e Listeria monocytogenes
UMUC's Presence at the 13th Sloan-C International Conference - DE Oracle
No full textDE Oracle @ UMUC
An Online Learning Magazine for UMUC Faculty
Center for Support of Instruction
UMUC's Presence at the 13th Sloan-C International Conference
Heloisa Siffert
Senior Instructional Support Specialist
Center for Support of Instruction
Published: January-February 2008
Category: » University-showcase » Papers-studies
UMUC made a remarkable presence at the 13th Sloan-C Conference that was held in Orlando, Florida,
November 7-9. The Sloan-C Consortium, which hosts the annual conference, is one of the fastest
growing and pre-eminent organizations dedicated to the growth and accessibility of online learning. The
total attendance of the 2007 conference was over 1200 people, representing college faculty and
administrators, instructional technology professionals and designers from various states and countries.
Relative to this year’s theme, The Power of Online Learning: Making a Difference, UMUC presenters
from various departments spoke on topics ranging from best instructional practices to faculty
development to emerging trends.
Below are the abstracts for all UMUC presentations:
International Perspectives on Online Learning
Nick Allen, ICDE (and UMUC Provost Emeritus); Armando Villarroel, CREAD; and Martine Vidal, EDEN
This panel presentation, provided perspectives on trends in online learning from three international
organizations: the Inter-American Distance Education Consortium (CREAD); the European Distance and
e-Learning Network (EDEN); and the International Council for Open and Distance Education (ICDE).
Developing Online Learning Objects to Support Positive Faculty-Student Interaction
Betsy Alperin, Laurie Hulcher, and Heloisa Siffert, UMUC
The limits of expression in the distance education environment can make positive faculty-student
interaction a challenge for even the most dedicated educators. This session showcased the
development of an online faculty workshop that uses a video case study model to strengthen and
support skills in this area. (power point presentation (http://www.ce.ucf.edu/asp/aln/cfp/presentations
/1191429990373.ppt) )
Competency Development in Blended and Online Business Learning Environments
Jomarie Bliss, Jane Ross, Jacob Krivoruchko, Lee Ann Graul and Frank Albritton, UMUC
UMUC's online MBA program features the integration of competencies into instruction, assignments and
feedback, as a key part of its innovative curriculum design. By emphasizing ten specific competencies,
faculty encourages students to connect classroom experiences with real-world skills and promote
increased collaboration, personal growth, and greater depth of learning. (power point presentation
(http://polaris.umuc.edu/de/csi/sloan_c/mba/Sloan%20Conference%20UMUC%20presentation%2011-07%20final.ppt) )
Creating a Multi-Cultural Online Classroom through Blogs, Wikis, and Connect
Richard Schumaker and Lisa Ellen Bernstein, UMUC
This presentation explored three new technologies that present diversity themes in an intellectually
rigorous and pedagogically sound fashion. The emphasis was at once theoretical and practical:
formulating key theoretical issues, as well as providing practical examples of successful examples in
UMUC's Presence at the 13th Sloan-C International Conference - DE Oracle
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teaching diversity issues using new technologies. The presenters demonstrated the use of the UMUC
"Chaucer server," developed by Theo Stone.
E-learning to the Rescue: Cases in the United States, South Africa and Lebanon
Claudine SchWeber, UMUC, and Maureen Yoder, Lesley University
Sometimes e-learning is the best, and only, solution to unexpected developments or serious business
challenges. This session described cases in the United States, Lebanon, and South Africa,
demonstrating how e-learning provided opportunities for the education and business communities to
continue operations despite threats to their ability to function.
Learning Foreign Languages Online: UMUC's Innovative Approach
Gretchen Jones and Alana Fennie, UMUC
This session showcased the innovative approaches in designing online foreign language courses and the
technologies that support the design. The session outlined how UMUC adapted learning theories to
meet the needs of online educators and students. The session also demonstrated unique integration of
technology supporting the course design.
A Job Well Done!
Once again Sloan-C Conference was an extraordinary opportunity for UMUC faculty, instructional
technologists and administrators to share our experiences and practices with an international
community of distance learning educators. Let's acknowledge our presenters and their supporting
teams for the hard work well done. Great job, UMUC!
About the Author(s)
Heloisa Siffert Senior Instructional Support Specialist, Center for Support of Instruction, develops and delivers faculty training
programs, and collaborates with the academic units on online classroom setup, course design, learning objects development
and implementations of new technologies. Her areas of expertise include graphic design and web/multimedia development.
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The constancy of global regulation across a species: the concentrations of ppGpp and RpoS are strain-specific in Escherichia coli
No full textBackground: Sigma factors and the alarmone ppGpp control the allocation of RNA polymerase to promoters under stressful conditions. Both ppGpp and the sigma factor sigma(S) (RpoS) are potentially subject to variability across the species Escherichia coli. To find out the extent of strain variation we measured the level of RpoS and ppGpp using 31 E. coli strains from the ECOR collection and one reference K-12 strain. Results: Nine ECORs had highly deleterious mutations in rpoS, 12 had RpoS protein up to 7-fold above that of the reference strain MG1655 and the remainder had comparable or lower levels. Strain variation was also evident in ppGpp accumulation under carbon starvation and spoT mutations were present in several low-ppGpp strains. Three relationships between RpoS and ppGpp levels were found: isolates with zero RpoS but various ppGpp levels, strains where RpoS levels were proportional to ppGpp and a third unexpected class in which RpoS was present but not proportional to ppGpp concentration. High-RpoS and high-ppGpp strains accumulated rpoS mutations under nutrient limitation, providing a source of polymorphisms. Conclusions: The ppGpp and sigma(S) variance means that the expression of genes involved in translation, stress and other traits affected by ppGpp and/or RpoS are likely to be strain-specific and suggest that influential components of regulatory networks are frequently reset by microevolution. Different strains of E. coli have different relationships between ppGpp and RpoS levels and only some exhibit a proportionality between increasing ppGpp and RpoS levels as demonstrated for E. coli K-12.Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP - Brazil)Australian Endeavour Research FellowshipAustralian Research Counci
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