Studies of a novel conducting polymer by cyclic and square wave voltammetries: Its synthesis and characterization

A novel conducting polymer of polynaphthidine, poly(NAP), was synthesized electrochemically by direct anodic oxidation of naphthidine in aqueous media. The yield of the electropolymerization reaction depends on the temperature and pH of the solution. It was possible to differentiate two working regions: I (for pH 15 °C) where the film production is maximum. Therefore, the naphthidine electrooxidation mechanism was studied under experimental conditions of region I by cyclic (CV) and square wave voltammetries (SWV) as well as by controlled potential electrolysis. The experimental conditions of region II were chosen to obtain the poly(NAP). The electrochemical response of the film was investigated in pH 1 HClO4 + 0.1 M NaClO4 electrolyte solution by CV and SWV. A plot of Ip,n/f vs. f from SW voltammograms showed the so-called “quasi-reversible maximum”. Formal potential, formal rate constant and anodic transfer coefficient for the surface redox process were also evaluated from the SWV. The poly(NAP) is insoluble in common organic solvents and shows electrochromic behaviour. Its probable structure was determined by FTIR spectroscopy.Fil: D'eramo, Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Zon, María Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Fernandez, Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Sereno, Leonides Edmundo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Arévalo, Alejandro Heraldo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentin

Bacteriological and Immunological Profiling of Meconium and Fecal Samples from Preterm Infants : A Two-Year Follow-Up Study

An abnormal colonization pattern of the preterm gut may affect immune maturation and exert a long-term influence on the intestinal bacterial composition and host health. However, follow-up studies assessing the evolution of the fecal microbiota of infants that were born preterm are very scarce. In this work, the bacterial compositions of fecal samples, obtained from sixteen 2-year-old infants were evaluated using a phylogenetic microarray; subsequently, the results were compared with those obtained in a previous study from samples of meconium and feces collected from the same infants while they stayed in the neonatal intensive care unit (NICU). In parallel, the concentration of a wide range of cytokines, chemokines, growth factors and immunoglobulins were determined in meconium and fecal samples. Globally, a higher bacterial diversity and a lower interindividual variability were observed in 2-year-olds' feces, when compared to the samples obtained during their first days of life. Hospital-associated fecal bacteria, that were dominant during the NICU stay, seemed to be replaced, two years later, by genera, which are usually predominant in the healthy adult microbiome. The immune profile of the meconium and fecal samples differed, depending on the sampling time, showing different immune maturation statuses of the gut.Peer reviewe

Bacterial Diversity in Meconium of Preterm Neonates and Evolution of Their Fecal Microbiota during the First Month of Life

Peer reviewe

Condiciones de produccion de proteasa y lipasa extracelulares de 'Pseudomonas fluorescens' y su relevancia en la leche cruda refrigerada

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

The bacteriocin nisin, an effective agent for the treatment of staphylococcal mastitis during lactation

Eight women with clinical signs of staphylococcal mastitis were randomly divided in 2 groups. A solution of the bacteriocin nisin (6 tg/mQ was applied to the nipple and mammary areola of those assigned to the nisin group for 2 weeks, and a similar preparation devoid of nisin was applied to the control group. On day 0, staphylococcal counts in breast milk of the nisin and control groups were similar (5.04 0.19 and 4.88 0.21 log,0 CFU/mL, respectively). However, on day 14, the mean in the nisin group (3.22 0.43 log,, CFU/mL) was statistically lower than that of the control group (5.01 0.21 log,0 CFU/mL). No clinical signs of mastitis were observed among the women of the nisin group on day 14, whereas they persisted throughout the study in the women of the control group. In conclusion, nisin seems to be an efficient alternative to antibiotics for the treatment of staphylococcal mastitis.</p

The bacteriocin nisin, an effective agent for the treatment of staphylococcal mastitis during lactation

Eight women with clinical signs of staphylococcal mastitis were randomly divided in 2 groups. A solution of the bacteriocin nisin (6 tg/mQ was applied to the nipple and mammary areola of those assigned to the nisin group for 2 weeks, and a similar preparation devoid of nisin was applied to the control group. On day 0, staphylococcal counts in breast milk of the nisin and control groups were similar (5.04 0.19 and 4.88 0.21 log,0 CFU/mL, respectively). However, on day 14, the mean in the nisin group (3.22 0.43 log,, CFU/mL) was statistically lower than that of the control group (5.01 0.21 log,0 CFU/mL). No clinical signs of mastitis were observed among the women of the nisin group on day 14, whereas they persisted throughout the study in the women of the control group. In conclusion, nisin seems to be an efficient alternative to antibiotics for the treatment of staphylococcal mastitis.</p

Inhibition of Human Immunodeficiency Virus Type 1 by Lactic Acid Bacteria from Human Breastmilk

BACKGROUND: Human breastmilk provides a rich source of commensal lactic acid bacteria (LAB) to the infant during breastfeeding and stimulates abundant growth and colonization of these bacteria at mucosal surfaces in the infant gastrointestinal tract. While conferring critical nutritional and immunologic support to the developing newborn, breastmilk also serves as a vehicle for human immunodeficiency virus type 1 (HIV-1) transmission from mother to child during breastfeeding. Whether breastmilk LAB confer protection against mucosal exposure to HIV-1 in breastfeeding infants is unknown. STUDY DESIGN: In the present study, we sought to evaluate LAB isolated from the breastmilk of healthy women for the ability to inhibit HIV-1 infection in vitro. A total of 38 strains of breastmilk bacteria were evaluated in this study. Both heat-killed bacteria and cell-free conditioned supernatants from bacterial cultures were tested for the ability to inhibit infection with HIV-1 using viral isolates with tropism for CCR5 (R5), CXCR4 (X4), or R5/X4 dual-tropism. RESULTS: Significant inhibition of R5-tropic HIV-1 was demonstrated using heat-killed bacteria, most notably among breastmilk strains of Lactobacillus and Pediococcus. Selected strains of breastmilk LAB also demonstrated significant inhibition of HIV-1 infection against virus with tropism for X4 and R5/X4. CONCLUSION: These results demonstrate for the first time that commensal LAB from human breastmilk inhibit HIV-1 infection in vitro and suggest a possible role for these bacteria in mucosal protection against HIV-1 in the breastfeeding infant