Investigations on the efficacy of monovalent Pseudomonas aeruginosa vaccine for oral administration in Pseudomonas aeruginosa experimental infection

Therapeutic efficacy of Pseudomonas aeruginosa vaccine for oral use (10(10) killed germs/ml), prepared from strain 4922, belonging to serotype XV, by Meitert-Meitert scheme, on 4 experimental models in mice (pneumonia, infected burn, septicaemia and urinary tract infection) was studied in comparison with monovalent Ps. aeruginosa vaccine serotype XV (10(9) killed germs/ml) for subcutaneous use and also with associated administration of the two vaccine variants. Mice immunization by using vaccine for oral use was performed by 0.5 ml vaccine per day, for 10 days and vaccine for subcutaneous use was administrated in a volume of 0.5 ml x 2, at 3 days interval. Mice immunization by using the two vaccine types, in association was concomitantly performed and in the same quantity as for separate immunization. In experimental pneumonia, Ps. aeruginosa vaccine for oral use protected mice in 35% of cases, those with infected burns were protected in 33.3% of cases, those with septicemia--in 96.6% of cases and those with urinary tract infection in 50% of cases. As compared to Ps. aeruginosa vaccine for subcutaneous use, the results obtained by vaccine for oral use are less favourable but associated administration of both vaccine variants led to superior results. Thus, in experimental pneumonia, it was obtained a surviving rate of 65% for animals immunized with both vaccine types, in comparison with 50% for animals immunized with vaccine for subcutaneous use only, and in Ps. aeruginosa infected burn, it was obtained a recovering rate of 79.1% for the animals immunized by using both vaccines, in comparison with 70.8% surviving for animals immunized with vaccine for subcutaneous use. In experimental septicaemia and urinary tract infection, combined use of both vaccine variants determined animals surviving and recovering in percents similar to those obtained by separate administration of vaccine for subcutaneous use (in septicemia--100% protection; in urinary tract infection--75% protection).     

Melatonin and TiO2 NPs Application-Induced Changes in Growth,Photosynthesis, Antioxidant Enzymes Activities and Secondary Metabolites in Stevia (Stevia rebaudiana Bertoni) Under Drought Stress Conditions

Journal of Plant Growth Regulation - Drought stress is one of the major constraints on the growth and productivity of crop plants. Recently, new approaches have been employed in order to cope with...     

Effect of Heat, Acidification, and Chlorination on Salmonella enterica Serovar Typhimurium Cells in a Biofilm Formed at the Air-Liquid Interface

Bacterial biofilms have great significance for public health, since biofilm-associated microorganisms exhibit dramatically decreased susceptibility to antimicrobial agents and treatments. To date most attention has focused on biofilms that arise from the colonization of solid-liquid or solid-air interfaces. It is of interest that colonization of the interface between air and liquid, which can be selectively advantageous for aerobic or facultative aerobic bacteria, has been rarely studied, although it may present a major problem in industrial aquatic systems. In this work we investigated the role of a biofilm at the interface between air and liquid (pellicle) in the susceptibility of Salmonella enterica serovar Typhimurium to stress conditions. For a control we used a mutant that had lost its ability to synthesize cellulose and thin aggregative fimbriae and thus did not produce the pellicle. Resistance of bacteria from the pellicle to heat, acidification, and chlorination was compared to resistance of planktonic cells from the logarithmic and stationary phases of growth. Pellicle cells were significantly more resistant to chlorination, and thus the surrounding matrix conferred protection against the reactive sodium hypochlorite. However, the stress management of pellicle cells in response to heat and low pH was not enhanced compared to that of stationary-phase cells. A long-period of incubation resulted in endogenous hydrolysis of the pellicle matrix. This phenomenon provides a potential new approach to combat microbial cells in biofilms.     

Human C-peptide Dose Dependently Prevents Early Neuropathy in the BB/Wor-rat

In order to explore the neuroprotective and crossspecies activities of.C-peptide on type 1 diabetic neuropathy, spontaneously diabetic BB/W-rats were given increasing doses of human recombinant Cpeptide (hrC-peptide). Diabetic rats received 10, 100, 500, or 1000 μg of hrC-peptide/kg body weight/ day from onset of diabetes. After 2 months of hrC-peptide administration, 100 μg and greater doses completely prevented the nerve conduction defect, which was associated with a significant but incomplete prevention of neural Na⁺/K⁺-ATPase activity in diabetic rats with 500 μg or greater C-peptide replacement. Increasing doses of hrC-peptide showed increasing prevention of early structural abnormalities such as paranodal swelling and axonal degeneration and an increasing frequency of regenerating sural nerve fibers. We conclude that hrC-peptide exerts a dose dependent protection on type 1 diabetic neuropathy in rats and that this effect is probably mediated by the partially conserved sequence of the active C-terminal pentapeptide     

Immunological and genetic evidence for a crucial role of IL-10 in cutaneous lesions in humans infected with Leishmania braziliensis

In populations exposed to Leishmania braziliensis, certain subjects develop skin ulcers, whereas others are naturally protected against cutaneous leishmaniasis. We have evaluated which cytokines are most crucial in the development of skin lesions. We found that active lesions occur in subjects with polarized Th2 or mixed Th1/Th2 responses, both associated with elevated IL-10 production. IL-10 was strongly associated (p = 0.004, odd ratio (OR) = 6.8, confidence interval = 1.9-25) with lesions, excluding IFN-gamma, IL-12, TNF, IL-13, and IL-4 from the regression model. IL-10 was produced by blood monocytes and CD4(+)CD25(+) T lymphocytes (mostly Foxp3(+)). However, we did not observe any difference between the number of these cells present in the blood of subjects with active lesions and those present in resistant subjects. Genetic analysis of the IL10-819C/T polymorphism, located in the IL10 promoter, showed that the C allele increased the risk of lesions (OR = 2.5 (1.12-5.7), p = 0.003). Functional analysis of these variants showed allele-specific binding of nuclear factors. The IL10-819C/C genotype was associated with higher levels of IL-10 than C/T and T/T genotypes. These observations demonstrate an important role for IL-10 in skin lesions in humans infected with L. braziliensis, and identify circulating monocytes and Tregs as principal sources of IL-10 in these patients.     

Sucrose supply enhances phosphoenolpyruvate carboxylase phosphorylation level in in vitro Solanum tuberosum

In order to study the effect of exogenous sucrose on the phosphorylation of phosphoenolpyuruvate carboxylase (PEPC), potato plantlets (Solanum tuberosum L. cv. Kennebec) were grown on three modifications of the Murashige and Skoog (MS) medium: 3% sucrose + normal N level (1% Suc + N); 3% sucrose + normal N level (3% Suc + N); 3% sucrose + reduced N level (3% Suc – N). After 20 days of culture, PEPC phosphorylation levels were determined in leaves and roots by means of protein labelling with ³²P, and by L-malate inhibition of enzyme activity. Plants grown with 3% Suc + N had the highest phosphorylation level compared to those cultured with 3% Suc and the control (1% Suc + N). These investigations demonstrated clearly that sucrose enhanced phosphorylation. Sucrose or its metabolism may cause PEPC to become less sensitive to L-malate inhibition.     

Coordinated lipid transfer between the endoplasmic reticulum and the Golgi complex requires the VAP proteins and is essential for Golgi-mediated transport

Lipid transport between intracellular organelles is mediated by vesicular and nonvesicular transport mechanisms and is critical for maintaining the identities of different cellular membranes. Nonvesicular lipid transport between the endoplasmic reticulum (ER) and the Golgi complex has been proposed to affect the lipid composition of the Golgi membranes. Here, we show that the integral ER-membrane proteins VAP-A and VAP-B affect the structural and functional integrity of the Golgi complex. Depletion of VAPs by RNA interference reduces the levels of phosphatidylinositol-4-phosphate (PI4P), diacylglycerol, and sphingomyelin in the Golgi membranes, and it leads to substantial inhibition of Golgi-mediated transport events. These effects are coordinately mediated by the lipid-transfer/binding proteins Nir2, oxysterol-binding protein (OSBP), and ceramide-transfer protein (CERT), which interact with VAPs via their FFAT motif. The effect of VAPs on PI4P levels is mediated by the phosphatidylinositol/phosphatidylcholine transfer protein Nir2, which is required for Golgi targeting of OSBP and CERT and the subsequent production of diacylglycerol and sphingomyelin. We propose that Nir2, OSBP, and CERT function coordinately at the ER-Golgi membrane contact sites, thereby affecting the lipid composition of the Golgi membranes and consequently their structural and functional identities.     

Branched aminoglycosides: biochemical studies and antibacterial activity of neomycin B derivatives

The C5'-OH group in neomycin B was glycosylated with a variety of mono- and di-saccharides to probe the effect of introduction of additional binding elements on antibacterial activity and interaction with the aminoglycosides modifying enzyme APH(3')-IIIa. The designed structures show antibacterial activity superior to that of neomycin B against pathogenic and resistant strains, while in parallel they demonstrate poor substrate activity with APH(3')-IIIa.