Francesco Tessarolo

Morpho-functional asymmetry of the olfactory receptors of the honeybee (Apis mellifera).

Lateralization, i.e., the different functional specialisation of the left and right side of the brain, has been documented in many vertebrate species and, recently, in invertebrate species as well. In the Honeybee, Apis mellifera L. (Hymenoptera Apidae), it has been shown that short-term (<1h) recall of olfactory memories would be possible mainly from the right rather than from the left antenna. Here we confirmed this finding showing that recall of the olfactory memory 1h after training to associate (-)-linalool, a floral volatile compound, with a sugar reward, as revealed by the bee extending its proboscis when presented with the trained odour, was better when the odour was presented to the right rather than to the left antenna. We then measured the number of sensilla present on the left and right antenna by scanning electron microscopy. Results showed that putative olfactory sensilla (placodea, trichodea, basiconica) were significantly more abundant on the right antenna surface than on the left antenna surface, whereas sensilla not involved in olfaction (campaniformia, coeloconica and chaetica) tended to be more abundant on the left than on the right antenna surface.

Macromolecule Loading into Spherical, Elliptical, Star-Like and Cubic Calcium Carbonate Carriers

We fabricated calcium carbonate particles with spherical, elliptical, star-like and cubical morphologies by varying relative salt concentrations and adding ethylene glycol as a solvent to slow down the rate of particle formation. The loading capacity of particles of different isotropic (spherical and cubical) and anisotropic (elliptical and star-like) geometries is investigated, and the surface area of such carriers is analysed. Potential applications of such drug delivery carriers are highlighted.

Inhibition of Candida albicans adhesion on medical‐grade silicone by a Lactobacillus‐derived biosurfactant

The study aimed at investigating the ability of biosurfactant (BS) produced by a Lactobacillus brevis isolate (CV8LAC) to inhibit adhesion and biofilm formation of Candida albicans on medical‐grade silicone elastomeric disks (SEDs).

Sterility and Microbiological Assessment of Reused Single‐Use Cardiac Electrophysiology Catheters

OBJECTIVE To assess the performance and limitations of a reprocessing protocol for nonlumen electrophysiology catheters by testing the sterility of reprocessed devices and defining the maximum number of reprocessing cycles sustainable by the device in hygienically safe conditions. DESIGN Simulated use, reprocessing, and testing of the catheters. SETTING Microbiology and virology department of a public health diagnostic laboratory. INTERVENTIONS Seventy-three catheters were collected after clinical use on patients. The first group of devices was tested for sterility after 1 cycle of reprocessing. By the repetition of simulated use (blood inoculated with bacteria) and reprocessing (decontamination, cleaning, and hydrogen peroxide gas plasma sterilization), we obtained 39 sample devices reprocessed 2 times, 26 reprocessed 3 times, 28 reprocessed 4 times, 36 reprocessed 5 times, and 22 reprocessed 6 times. Devices were cultured for 28 days in trypticase soy broth. RESULTS We tested 208 catheters with 6 cycles of reprocessing and 4 inoculated bacteria species. No devices tested positive for the inoculated strains until the fourth cycle of reprocessing. One of 35 catheters showed the growth of the inoculated strain Bacillus subtilis after 5 cycles of reprocessing, and 1 of 22 catheters showed growth of this organism 6 cycles. After the second reprocessing, 7 of 36 devices showed growth of gram-negative bacteria other than the strain inoculated. CONCLUSIONS Reprocessing according to the reprocessing protocol was insufficient to guarantee device sterility after 5 reuses. Cleaning with enzymatic solution revealed good cleaning properties with efficient bioburden reduction. Storage intervals of longer than 24 hours during reprocessing should be avoided to limit contamination or bacterial overgrowth. Technical considerations suggest the introduction of reprocessing procedures only in hospitals with considerable workloads.

A multimodal approach for tracing lateralisation along the olfactory pathway in the honeybee through electrophysiological recordings, morpho-functional imaging, and behavioural studies

Recent studies have revealed asymmetries between the left and right sides of the brain in invertebrate species. Here we present a review of a series of recent studies from our laboratories, aimed at tracing asymmetries at different stages along the honeybee’s (Apis mellifera) olfactory pathway. These include estimates of the number of sensilla present on the two antennae, obtained by scanning electron microscopy, as well as electroantennography recordings of the left and right antennal responses to odorants. We describe investigative studies of the antennal lobes, where multi-photon microscopy was used to search for possible morphological asymmetries between the two brain sides. Moreover, we report on recently published results obtained by two-photon calcium imaging for functional mapping of the antennal lobe aimed at comparing patterns of activity evoked by different odours. Finally, possible links to the results of behavioural tests, measuring asymmetries in single-sided olfactory memory recall, are discussed.

Effects of Mushroom and Chicory Extracts on the Physiology and Shape of Prevotella intermedia, a Periodontopathogenic Bacterium

Contrary to the common assumption that food has a negative impact on oral health, research has shown that several foods contain a number of components with antibacterial and antiplaque activity. These natural compounds may be useful for improving daily oral hygiene. In this study we evaluate the mode of antimicrobial action of fractions of mushroom and red chicory extracts on Prevotella intermedia, a periodontopathogenic bacterium. The minimal inhibitory concentration corresponded to 0.5x compared to the natural food concentration for both extracts. This concentration resulted in a bacteriostatic effect in mushroom extract and in a slightly bactericidal effect in chicory extract. Cell mass continued to increase even after division stopped. As regards macromolecular synthesis, DNA was almost totally inhibited upon addition of either mushroom or chicory extract, and RNA to a lesser extent, while protein synthesis continued. Cell elongation occurred after septum inhibition as documented by scanning electron microscopy and cell measurement. The morphogenetic effects are reminiscent of the mode of action of antibiotics such as quinolones or β-lactams. The discovery of an antibiotic-like mode of action suggests that these extracts can be advantageously employed for daily oral hygiene in formulations of cosmetic products such as mouthwashes and toothpastes.

Blood flow in hemodialysis catheters: a numerical simulation and microscopic analysis of in vivo-formed fibrin.

Although catheters with side holes allow high flow rate during hemodialysis, they also induce flow disturbances and create a critical hemodynamic environment that can favor fibrin deposition and thrombus formation. This study compared the blood flow and analyzed the influence of shear stress and shear rate in fibrin deposition and thrombus formation in nontunneled hemodialysis catheters with unobstructed side holes (unobstructed device) or with some side holes obstructed by blood thrombi (obstructed device). Computational fluid dynamics (CFD) was performed to simulate realistic blood flow under laminar and turbulent conditions. The results from the numerical simulations were compared with the fibrin distribution and thrombus architecture data obtained from scanning electron microscopy (SEM) and two photons laser scanning microscopy (TPLSM) on human thrombus formed in catheters removed from patients. CFD showed that regions of flow eddies and separation were mainly found in the venous holes region. TPLSM characterization of thrombi and fibrin structure in patient samples showed fibrin formations in accordance with simulated flux dynamics. Under laminar flow conditions, the wall shear stress close to border holes increased from 87.3±0.2 Pa in the unobstructed device to 176.2±0.5 Pa in the obstructed one. Under turbulent flow conditions, the shear stress increased by 47% when comparing the obstructed to the unobstructed catheter. The shear rates were generally higher than 5000/s and therefore sufficient to induce fibrin deposition. This findings were supported by SEM data documenting a preferential fibrin arrangement on side hole walls.

Dependence of Sub-Micron Vaterite Container Release Properties on pH and Ionic Strength of the Surrounding Solution

We report on the synthesis and characterization of porous monodisperse vaterite containers with controllable average sizes from 400 nm to 10 μm. Possible release strategies of enclosed substances via recrystallization or by pH-change are presented. As a model experiment, a fluorescent marker was encapsulated and imaged by two-photon microscopy to monitor the dye release. The release process was found to be controllable via the immersion medium’s properties. Release times can be further tuned by covering the containers with additional polymer layers, creating a flexible system with promising perspectives for pharmaceutical applications.

Effects of mushroom and chicory extracts on the shape, physiology and proteome of the cariogenic bacterium Streptococcus mutans

BackgroundDental caries is an infectious disease which results from the acidic demineralisation of the tooth enamel and dentine as a consequence of the dental plaque (a microbial biofilm) accumulation. Research showed that several foods contain some components with antibacterial and antiplaque activity. Previous studies indicated antimicrobial and antiplaque activities in a low-molecular-mass (LMM) fraction of extracts from either an edible mushroom (Lentinus edodes) or from Italian red chicory (Cichorium intybus).MethodsWe have evaluated the antimicrobial mode of action of these fractions on Streptococcus mutans, the etiological agent of human dental caries. The effects on shape, macromolecular syntheses and cell proteome were analysed.ResultsThe best antimicrobial activity has been displayed by the LMM mushroom extract with a bacteriostatic effect. At the MIC of both extracts DNA synthesis was the main macromolecular synthesis inhibited, RNA synthesis was less inhibited than that of DNA and protein synthesis was inhibited only by roughly 50%. The partial inhibition of protein synthesis is compatible with the observed significant increase in cell mass. The increase in these parameters is linked to the morphological alteration with transition from cocci of the untreated control to elongated cells. Interestingly, these modifications were also observed at sub-MIC concentrations. Finally, membrane and cytosol proteome analysis was conducted under LMM mushroom extract treatment in comparison with untreated S. mutans cells. Significant changes were observed for 31 membrane proteins and 20 of the cytosol fractions. The possible role of the changed proteins is discussed.ConclusionsThis report has shown an antibiotic-like mode of action of mushroom and chicory extracts as demonstrated by induced morphogenetic effects and inhibition of specific macromolecular synthesis. This feature as well as the safe use of this extract as result of its natural origin render the LMM both mushroom and chicory extracts suitable for the formulation into products for daily oral hygiene such as mouthwashes or toothpastes.

Selection of reference genes is critical for miRNA expression analysis in human cardiac tissue. A focus on atrial fibrillation

MicroRNAs (miRNAs) are emerging as key regulators of complex biological processes in several cardiovascular diseases, including atrial fibrillation (AF). Reverse transcription-quantitative polymerase chain reaction is a powerful technique to quantitatively assess miRNA expression profile, but reliable results depend on proper data normalization by suitable reference genes. Despite the increasing number of studies assessing miRNAs in cardiac disease, no consensus on the best reference genes has been reached. This work aims to assess reference genes stability in human cardiac tissue with a focus on AF investigation. We evaluated the stability of five reference genes (U6, SNORD48, SNORD44, miR-16, and 5S) in atrial tissue samples from eighteen cardiac-surgery patients in sinus rhythm and AF. Stability was quantified by combining BestKeeper, delta-Cq, GeNorm, and NormFinder statistical tools. All methods assessed SNORD48 as the best and U6 as the worst reference gene. Applications of different normalization strategies significantly impacted miRNA expression profiles in the study population. Our results point out the necessity of a consensus on data normalization in AF studies to avoid the emergence of divergent biological conclusions.