Transcriptome and membrane fatty acid analyses reveal different strategies for responding to permeating and non-permeating solutes in the bacterium Sphingomonas wittichii.

ABSTRACT: BACKGROUND: Sphingomonas wittichii strain RW1 can completely oxidize dibenzo-p-dioxins and dibenzofurans, which are persistent contaminants of soils and sediments. For successful application in soil bioremediation systems, strain RW1 must cope with fluctuations in water availability, or water potential. Thus far, however, little is known about the adaptive strategies used by Sphingomonas bacteria to respond to changes in water potential. To improve our understanding, strain RW1 was perturbed with either the cell-permeating solute sodium chloride or the non-permeating solute polyethylene glycol with a molecular weight of 8000 (PEG8000). These solutes are assumed to simulate the solute and matric components of the total water potential, respectively. The responses to these perturbations were then assessed and compared using a combination of growth assays, transcriptome profiling, and membrane fatty acid analyses. RESULTS: Under conditions producing a similar decrease in water potential but without effect on growth rate, there was only a limited shared response to perturbation with sodium chloride or PEG8000. This shared response included the increased expression of genes involved with trehalose and exopolysaccharide biosynthesis and the reduced expression of genes involved with flagella biosynthesis. Mostly, the responses to perturbation with sodium chloride or PEG8000 were very different. Only sodium chloride triggered the increased expression of two ECF-type RNA polymerase sigma factors and the differential expression of many genes involved with outer membrane and amino acid metabolism. In contrast, only PEG8000 triggered the increased expression of a heat shock-type RNA polymerase sigma factor along with many genes involved with protein turnover and repair. Membrane fatty acid analyses further corroborated these differences. The degree of saturation of membrane fatty acids increased after perturbation with sodium chloride but had the opposite effect and decreased after perturbation with PEG8000. CONCLUSIONS: A combination of growth assays, transcriptome profiling, and membrane fatty acid analyses revealed that permeating and non-permeating solutes trigger different adaptive responses in strain RW1, suggesting these solutes affect cells in fundamentally different ways. Future work is now needed that connects these responses with the responses observed in more realistic scenarios of soil desiccation.

Suurlähettiläs R.R. Seppälä 13/1 1967

Kirje

Tal vid sibeliusveckans öppningshögtidlighet år 1955

Puhe

The major genetic determinants of HIV-1 control affect HLA class I peptide presentation.

Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection.

External morphology of the immature stages of Neotropical heliconians: IX. Dione glycera (C. Felder & R. Felder) (Lepidoptera, Nymphalidae, Heliconiinae)

External morphology of the immature stages of Neotropical heliconians: IX. Dione glycera (C. Felder & R. Felder) (Lepidoptera, Nymphalidae, Heliconiinae). The biology of the Andean silverspot butterfly Dione glycera (C. Felder & R. Felder, 1861) is still poorly known. This species is restricted to high elevations in the Andes, where the immature stages are found in close association with species of Passiflora belonging to the section Tacsonia (Juss.) Harms, especially P. tripartida var. mollissima (Kunth), which is grown for subsistence by villagers. Herein we describe and illustrate the external features of the egg, larva and pupa of D. glycera, based on light and scanning electron microscopy.

Controlo Interno e Gestão dos Correios de Cabo Verde S.A.R.L

O trabalho que ora se apresenta tem como tema “controlo interno e gestão dos correios de Cabo Verde S.A.RL” e enquadra-se no âmbito do curso de licenciatura em Economia e Gestão, variante Auditoria Financeira, realizado pela Universidade Jean Piaget de Cabo Verde. O controlo interno tem sido implementado pelas empresas como modelo de gestão com o objectivo de auxiliar a administração na tomada de decisões. Perante esta situação, as dificuldades enfrentadas para criar e gerir essas áreas de acordo com os princípios da sustentabilidade, constituem constrangimentos e desafios que requerem medidas de políticas adequadas.O presente trabalho tem por objectivo analisar o sistema de controlo interno dos Correios Cabo Verde e evidenciar a importância do controlo interno como instrumento que contribua para uma melhor gestão da Empresa. Para a realização deste trabalho foi utilizada a metodologia qualitativa e exploratória, com enfoque para análise interna e externa, de forma a identificar os pontos fortes e fracos, as oportunidades e ameaças sobre o controlo interno e gestão dos correios cabo verde. Com a realização deste trabalho conclui-se com base na análise SWOT, que para além das suas potencialidades, possuem fraquezas e ameaças que condicionam a sua gestão, o que deve ser superado recorrendo a implementação de políticas de sustentabilidade, aproveitando assim, as oportunidades a esse respeito ser criativo e inovador.Pelo exposto, aconselha-se o refor��o de medidas, politicas e estratégias que contribuam para a eficácia do controlo interno.