Anti-infectives in Drug Delivery-Overcoming the Gram-Negative Bacterial Cell Envelope.

Infectious diseases are becoming a major menace to the state of health worldwide, with difficulties in effective treatment especially of nosocomial infections caused by Gram-negative bacteria being increasingly reported. Inadequate permeation of anti-infectives into or across the Gram-negative bacterial cell envelope, due to its intrinsic barrier function as well as barrier enhancement mediated by resistance mechanisms, can be identified as one of the major reasons for insufficient therapeutic effects. Several in vitro, in silico, and in cellulo models are currently employed to increase the knowledge of anti-infective transport processes into or across the bacterial cell envelope; however, all such models exhibit drawbacks or have limitations with respect to the information they are able to provide. Thus, new approaches which allow for more comprehensive characterization of anti-infective permeation processes (and as such, would be usable as screening methods in early drug discovery and development) are desperately needed. Furthermore, delivery methods or technologies capable of enhancing anti-infective permeation into or across the bacterial cell envelope are required. In this respect, particle-based carrier systems have already been shown to provide the opportunity to overcome compound-related difficulties and allow for targeted delivery. In addition, formulations combining efflux pump inhibitors or antimicrobial peptides with anti-infectives show promise in the restoration of antibiotic activity in resistant bacterial strains. Despite considerable progress in this field however, the design of carriers to specifically enhance transport across the bacterial envelope or to target difficult-to-treat (e.g., intracellular) infections remains an urgently needed area of improvement. What follows is a summary and evaluation of the state of the art of both bacterial permeation models and advanced anti-infective formulation strategies, together with an outlook for future directions in these fields

Lysine harvesting is an antioxidant strategy and triggers underground polyamine metabolism

Both single and multicellular organisms depend on anti-stress mechanisms that enable them to deal with sudden changes in the environment, including exposure to heat and oxidants. Central to the stress response are dynamic changes in metabolism, such as the transition from the glycolysis to the pentose phosphate pathway—a conserved first-line response to oxidative insults1,2. Here we report a second metabolic adaptation that protects microbial cells in stress situations. The role of the yeast polyamine transporter Tpo1p3,4,5 in maintaining oxidant resistance is unknown6. However, a proteomic time-course experiment suggests a link to lysine metabolism. We reveal a connection between polyamine and lysine metabolism during stress situations, in the form of a promiscuous enzymatic reaction in which the first enzyme of the polyamine pathway, Spe1p, decarboxylates lysine and forms an alternative polyamine, cadaverine. The reaction proceeds in the presence of extracellular lysine, which is taken up by cells to reach concentrations up to one hundred times higher than those required for growth. Such extensive harvest is not observed for the other amino acids, is dependent on the polyamine pathway and triggers a reprogramming of redox metabolism. As a result, NADPH—which would otherwise be required for lysine biosynthesis—is channelled into glutathione metabolism, leading to a large increase in glutathione concentrations, lower levels of reactive oxygen species and increased oxidant tolerance. Our results show that nutrient uptake occurs not only to enable cell growth, but when the nutrient availability is favourable it also enables cells to reconfigure their metabolism to preventatively mount stress protection

Coronavirus Gene 7 Counteracts Host Defenses and Modulates Virus Virulence

Transmissible gastroenteritis virus (TGEV) genome contains three accessory genes: 3a, 3b and 7. Gene 7 is only present in members of coronavirus genus a1, and encodes a hydrophobic protein of 78 aa. To study gene 7 function, a recombinant TGEV virus lacking gene 7 was engineered (rTGEV-Δ7). Both the mutant and the parental (rTGEV-wt) viruses showed the same growth and viral RNA accumulation kinetics in tissue cultures. Nevertheless, cells infected with rTGEV-Δ7 virus showed an increased cytopathic effect caused by an enhanced apoptosis mediated by caspase activation. Macromolecular synthesis analysis showed that rTGEV-Δ7 virus infection led to host translational shut-off and increased cellular RNA degradation compared with rTGEV-wt infection. An increase of eukaryotic translation initiation factor 2 (eIF2α) phosphorylation and an enhanced nuclease, most likely RNase L, activity were observed in rTGEV-Δ7 virus infected cells. These results suggested that the removal of gene 7 promoted an intensified dsRNA-activated host antiviral response. In protein 7 a conserved sequence motif that potentially mediates binding to protein phosphatase 1 catalytic subunit (PP1c), a key regulator of the cell antiviral defenses, was identified. We postulated that TGEV protein 7 may counteract host antiviral response by its association with PP1c. In fact, pull-down assays demonstrated the interaction between TGEV protein 7, but not a protein 7 mutant lacking PP1c binding motif, with PP1. Moreover, the interaction between protein 7 and PP1 was required, during the infection, for eIF2α dephosphorylation and inhibition of cell RNA degradation. Inoculation of newborn piglets with rTGEV-Δ7 and rTGEV-wt viruses showed that rTGEV-Δ7 virus presented accelerated growth kinetics and pathology compared with the parental virus. Overall, the results indicated that gene 7 counteracted host cell defenses, and modified TGEV persistence increasing TGEV survival. Therefore, the acquisition of gene 7 by the TGEV genome most likely has provided a selective advantage to the virus

Mortalidade de idosos em município do Sudeste brasileiro de 2006 a 2011

O objetivo foi descrever a mortalidade entre idosos em Araraquara (SP), no período de 2006 a 2011. Estudo epidemiológico descritivo, tendo como fontes de dados o Sistema de Informações sobre Mortalidade e a Fundação Sistema Estadual de Análise de Dados. Foi calculada razão entre coeficientes de mortalidade por ponto (R) e por intervalo de 95% de confiança (IC95%). Observou-se mais de 60% dos idosos com nível baixo de escolaridade, sendo que 76% faleceram em hospitais. Entre 2006 e 2008, as diferenças foram estatisticamente significantes entre homens e mulheres, predominando as doenças circulatórias com R = 1,41 (IC95%:1,24-1,58), respiratórias com R = 1,49 (IC95%:1,22-1,76) e neoplasias com R = 1,79 (IC95%: 1,40-2,18). Entre 2009 e 2011, obteve-se, para as causas circulatórias R = 1,18 (IC95%:1,03-1,33), sendo significativas as diferenças para as respiratórias com R = 1,33 (IC95%:1,11-1,55) e câncer sendo R = 1,94 (IC95%:1,53-2,35). O diabetes mellitus e as causas externas apareceram, respectivamente, como quarta e quinta causas de mortes mais frequentes na população idosa. O padrão de mortalidade encontrado ressalta a importância de ações voltadas à redução das principais causas de morte, como o incremento da cobertura da vacina contra a influenza e o controle da hipertensão arterial e do diabetes mellitus.This paper addressed the mortality rate for elderly people in Araraquara in the state of São Paulo between 2006 and 2011. An epidemiological descriptive study was conducted using data from the National Mortality Information System and the Data Analysis State System Foundation. The ratio between mortality rates by point (R) and by 95% confidence interval (IC95%) were estimated. More than 60% of elderly people had low education, and 76% of them died in hospital. For the period from 2006 to 2008 a statistically significant difference was observed between males and females, the most common causes of death being circulatory disease R = 1.41 (IC95%:1.24-1.58), respiratory problems R = 1.49 (IC95%:1.22-1.76), and cancer R = 1.79 (IC95%: 1.40-2.18). For the period from 2009 to 2011, circulatory diseases accounted for R=1.18 (IC95%:1.03-1.33)], and the differences were significant for respiratory disease R = 1.33 (IC95%:1.11-1.55) and cancer R = 1.94 (IC95%:1.53-2.35). The fourth and fifth more frequent causes of death among the elderly population were diabetes mellitus and external causes, respectively. The pattern of mortality found emphasizes the importance of actions aimed at reducing the major causes of death such as increasing the coverage of the influenza vaccine and control of hypertension and diabetes mellitus.Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Farmacêuticas de Araraquara Departamento de Ciências BiológicasUNESP Faculdade de Odontologia Departamento de Odontologia SocialUniversidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Farmacêuticas de Araraquara Departamento de Ciências BiológicasUNESP Faculdade de Odontologia Departamento de Odontologia Socia