Rational design of Salmonella-based vaccination strategies

A permanently growing body of information is becoming available about the quality of protective immune responses induced by mucosal immunization. Attenuated live bacterial vaccines can be administered orally and induce long-lasting protective immunity in humans without causing major side effects. An attenuated Salmonella enterica serovar Typhi strain is registered as live oral vaccine against typhoid fever and has been in use for more than two decades. Recombinant attenuated Salmonella strains are also an attractive means of delivering heterologous antigens to the immune system, thereby, stimulating strong mucosal and systemic immune responses and consequently provide an efficient platform technology to design novel vaccination strategies. This includes the choice of heterologous protective antigens and their expression under the control of appropriate promoters within the carrier strain. The availability of well-characterized attenuated mutants of Salmonella concomitantly supports fine tuning of immune response triggered against heterologous antigens. Exploring different mucosal sites as a potential route of immunization has to be taken into account as an additional important way to modulate immune responses according to clinical requirements. This article focuses on the rational design of strategies to modulate appropriate immunological effector functions on the basis of selection of (i) attenuating mutations of the Salmonella strains, (ii) specific expression systems for the heterologous antigens, and (iii) route of mucosal administration.     

Anti‐inflammatory properties of lemon‐derived extracellular vesicles are achieved through the inhibition of ERK/NF‐κB signalling pathways

Chronic inflammation is associated with the occurrence of several diseases. However, the side effects of anti‐inflammatory drugs prompt the identification of new therapeutic strategies. Plant‐derived extracellular vesicles (PDEVs) are gaining increasing interest in the scientific community for their biological properties. We isolated PDEVs from the juice of Citrus limon L. (LEVs) and characterized their flavonoid, limonoid and lipid contents through reversed‐phase high‐performance liquid chromatography coupled to electrospray ionization quadrupole time‐of‐flight mass spectrometry (RP‐HPLC–ESI‐Q‐TOF‐MS). To investigate whether LEVs have a protective role on the inflammatory process, murine and primary human macrophages were pre‐treated with LEVs for 24 h and then were stimulated with lipopolysaccharide (LPS). We found that pre‐treatment with LEVs decreased gene and protein expression of pro‐inflammatory cytokines, such as IL‐6, IL1‐β and TNF‐α, and reduced the nuclear translocation and phosphorylation of NF‐κB in LPS‐stimulated murine macrophages. The inhibition of NF‐κB activation was associated with the reduction in ERK1‐2 phosphorylation. Furthermore, the ability of LEVs to decrease pro‐inflammatory cytokines and increase anti‐inflammatory molecules was confirmed ex vivo in human primary T lymphocytes. In conclusion, we demonstrated that LEVs exert anti‐inflammatory effects both in vitro and ex vivo by inhibiting the ERK1‐2/NF‐κB signalling pathway.     

Identification and circumvention of bottlenecks in CYP21A2-mediated premedrol production using recombinant Escherichia coli

Synthetic glucocorticoids such as methylprednisolone are compounds of fundamental interest to the pharmaceutical industry as their modifications within the sterane scaffold lead to higher inflammatory potency and reduced side effects compared with their parent compound cortisol. In methylprednisolone production, the complex chemical hydroxylation of its precursor medrane in position C21 exhibits poor stereo- and regioselectivity making the process unprofitable and unsustainable. By contrast, the use of a recombinant E. coli system has recently shown high suitability and efficiency. In this study, we aim to overcome limitations in this biotechnological medrane conversion yielding the essential methylprednisolone-precursor premedrol by optimizing the CYP21A2-based whole-cell system on a laboratory scale. We successfully improved the whole-cell process in terms of premedrol production by (a) improving the electron supply to CYP21A2; here we use the N-terminally truncated version of the bovine NADPH-dependent cytochrome P450 reductase (bCPR₋₂₇) and coexpression of microsomal cytochrome b₅; (b) enhancing substrate access to the heme by modification of the CYP21A2 substrate access channel; and (c) circumventing substrate inhibition which is presumed to be the main limiting factor of the presented system by developing an improved fed-batch protocol. By overcoming the presented limitations in whole-cell biotransformation, we were able to achieve a more than 100% improvement over the next best system under equal conditions resulting in 691 mg·L⁻¹·d⁻¹ premedrol.     

Link between Geographical Origin and Occurrence of Brucella abortus Biovars in Cow and Water Buffalo Herds

Sixty-three Brucella isolates from water buffaloes and cattle slaughtered within the Italian national plan for brucellosis control were characterized by multiple-locus variable-number tandem repeat analysis (MLVA). Genotyping indicated a strong influence of geographic origin on the Brucella abortus biovar distribution in areas where brucellosis is endemic and highlighted the importance of rigorous management procedures aimed at avoiding inter- and intraherd spreading of pathogens.     

Weather daily variation in winter and its effect on behavior and affective states in day-care children

This study aimed to analyze the impact of winter weather conditions on young children’s behavior and affective states by examining a group of 61 children attending day-care centers in Florence (Italy). Participants were 33 males, 28 females and their 11 teachers. The mean age of the children at the beginning of the observation period was 24.1 months. The day-care teachers observed the children’s behavioral and emotional states during the morning before their sleeping time and filled in a questionnaire for each baby five times over a winter period of 3 weeks. Air temperature, relative humidity, air pressure and solar radiation data were collected every 15 min from a weather station located in the city center of Florence. At the same time, air temperature and relative humidity data were collected in the classroom and in the garden of each day-care center. We used multilevel linear models to evaluate the extent to which children’s emotional and behavioral states could be predicted by weather conditions, controlling for child characteristics (gender and age). The data showed that relative humidity and solar radiation were the main predictors of the children’s emotional and behavioral states. The outdoor humidity had a significant positive effect on frustration, sadness and aggression; solar radiation had a significant negative effect only on sadness, suggesting that a sunny winter day makes children more cheerful. The results are discussed in term of implications for parents and teachers to improve children’s ecological environment.     

Age‐dependent and task‐related volume changes in the mushroom bodies of visually guided desert ants,Cataglyphis bicolor

Desert ants of the genus Cataglyphis are skillful long‐distance navigators employing a variety of visual navigational tools such as skylight compasses and landmark guidance mechanisms. However, the time during which this navigational toolkit comes into play is extremely short, as the average lifetime of a Cataglyphis forager lasts for only about 6 days. Here we show, by using immunohistochemistry, confocal microscopy, and three‐dimensional reconstruction software, that even during this short period of adult life, Cataglyphis exhibits a remarkable increase in the size of its mushroom bodies, especially of the visual input region, the collar, if compared to age‐matched dark‐reared animals. This task‐related increase rides on a much smaller age‐dependent increase of the size of the mushroom bodies. Due to the variation in body size exhibited by Cataglyphis workers we use allometric analyses throughout and show that small animals exhibit considerably larger task‐related increases in the sizes of their mushroom bodies than larger animals do. It is as if there were an upper limit of mushroom body size required for accomplishing the ant's navigational tasks. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006