Heitt Mjölnir: a heated miniature triaxial apparatus for 4D synchrotron microtomography.

Third- and fourth-generation synchrotron light sources with high fluxes and beam energies enable the use of innovative X-ray translucent experimental apparatus. These experimental devices access geologically relevant conditions whilst enabling in situ characterization using the spatial and temporal resolutions accessible at imaging beamlines. Here, Heitt Mjölnir is introduced, a heated miniature triaxial rig based on the design of Mjölnir, but covering a wider temperature range and larger sample volume at similar pressure capacities. This device is designed to investigate coupled thermal, chemical, hydraulic and mechanical processes from grain to centimetre scales using cylindrical samples of 10 mm × 20 mm (diameter × length). Heitt Mjölnir can simultaneously reach confining (hydraulic) pressures of 30 MPa and 500 MPa of axial stress with independently controlled sample pore fluid pressure < 30 MPa. This internally heated apparatus operates to temperatures up to 573 K with a minimal vertical thermal gradient in the sample of <0.3 K mm-1. This new apparatus has been deployed in operando studies at the TOMCAT (Swiss Light Source), I12 JEEP (Diamond Light Source) and PSICHÉ (Synchrotron SOLEIL) beamlines for 4D X-ray microtomography with scan intervals of a few minutes. Heitt Mjölnir is portable and modular, allowing a wide range of 4D characterizations of low-grade metamorphism and deformational processes. It enables spatially and temporally resolved fluid-rock interaction studies at conditions of crustal reservoirs and is suitable for characterization of material properties in geothermal, carbonation or subsurface gas storage applications. Technical drawings and an operation guide are included in this publication.

Epidemiological aspects of dental trauma associated with maxillofacial injures: Ten years of clinical experience in Trieste, Italy.

BACKGROUND/AIMS: The prevalence of dental injuries in patients with facial fractures is relevant. Epidemiologically, dental trauma in association with facial fractures generally affects the age group between 20 and 40 years old, with a higher prevalence in males. The aim of this retrospective study was to identify the incidence and etiology of dental trauma associated with facial fractures over a 10-year period. METHODS: From January 2009 to April 2019, among 381 patients with facial fractures, 353 were included in this study. Age, gender, trauma etiology, injured teeth and dental treatment were investigated. RESULTS: From 353 patients, with a mean age of 49.7 ± 19.9 years, 247 (70%) were males and 106 (30%) were females. Accidental falls were the most common type of injury (n = 118, 33.4%), followed by road accidents (n = 90, 25.5%), assaults (n = 60, 17%) and sports trauma (n = 37, 10.5%). Fifty-five subjects (15.60%) had dental injuries associated with facial fractures. Of the 145 teeth involved, 48 (33.1%) were diagnosed with luxation, 22 teeth (15.2%) were avulsed, 11 teeth (7.5%) suffered a concussion and there were 10 (6.8%) alveolar wall fractures.Uncomplicated enamel-dentin fracture was the more frequent hard tissue injury (n = 21, 14.5%), followed by complicated crown-root fracture (n = 10, 6.9%), infraction (n = 8, 5.5%), enamel fracture (n = 3, 2%) and complicated enamel-dentin fracture (n = 3, 2%). There was a peak in incidence between 21 and 40 years (42%). Males had a significantly higher risk of facial fractures with dental injury (75%). Maxillary incisors and canines (62.8%) were the most affected teeth. CONCLUSIONS: There was a high prevalence of dental injuries associated with facial fractures. Maxillary incisors were the most injured teeth, with a higher prevalence in males.

Mandibular metastasis of pulmonary adenocarcinoma: How unexpected could it be?

OBJECTIVE: Metastatic tumours of bone must be considered in all patients with unexplained bone pain and particularly in patients who present with a known cancer, localised pain at multiple sites, and radiographic findings suggestive of metastasis. The purpose of this report was to present a case of a pathological fracture of the mandible as a consequence of metastatic pulmonary adenocarcinoma. MATERIALS AND METHODS: In July 2018 a 68-year-old male patient was hospitalised because of pulmonary adenocarcinoma and attended our department for an oral maxillo-facial evaluation. He complained of pain and swelling in the right temporomandibular region resulting in a reported functional limitation. An Orthopantomogram (OPG) demonstrated a right intracapsular condylar compound fracture associated with an osteolytic lesion at the condyle base with jagged margins. Subsequently, a CT scan with contrast of the maxillo-facial complex and a fine-needle aspiration of the lesion was performed. RESULTS: CT images showed the presence of a right mandibular condyle fracture associated with a large osteolytic lesion which confirmed the pathological nature of the fracture. Fine-needle aspiration of the lesion confirmed its metastatic nature. It was not possible to proceed with a mandibular resection due to the critical clinical condition of the patient who died in September 2018. CONCLUSION: Lung cancer frequently produces lytic-type metastasis, sometimes even in the jaw. In patients with an established diagnosis of lung cancer, any radiolucent lesion of the jaw or an unexplained painful symptomatology to the oro-maxillo facial complex should be placed in differential diagnosis with metastasis of the primary tumour.

Evaluating the stability of extended-pour alginate impression materials by using an optical scanning and digital method.

STATEMENT OF PROBLEM: The dimensional stability of alginate dental impressions is a key factor for the reliability of delayed gypsum pouring and digital scanning. However, studies of the dimensional stability of alginates with conventional methods that consider the dimensional variations of large impressions are lacking. PURPOSE: The purpose of this in vitro study was to investigate and compare 2 digital methods for the analysis of dimensional stability of large impressions made with 5 different extended-pour alginates and to assess dimensional stability up to 5 days. MATERIAL AND METHODS: Impressions of a simplified master maxillary model were made with Alginoplast, Blueprint, Hydrogum 5, Orthoprint, and Phase Plus and then analyzed at different time points. Digital scans of the alginate impression surfaces were obtained with a desktop scanner and analyzed by evaluating the linear measurements between reference points and by using a novel method that consists of the analysis of the entire scanned surface to evaluate the expansion and contraction of the impressions. RESULTS: The first method revealed that the dimensional changes did not exceed 0.5%, with the exception of Phase Plus at day 3 (-0.6 ±0.7%), and the average dimensional variation was always lower than or equal to 0.2 mm. Blueprint was the most stable material (-0.2 ±0.6%). The second method revealed dimensional variations always lower than 0.03 mm and confirmed Blueprint as the best performing material (0.001 ±0.006 mm) and Phase Plus the worst (-0.019 ±0.006 mm). CONCLUSIONS: Both the methods used to evaluate alginate stability showed that the analyzed materials remain stable over time; the dimensional variations showed a similar trend, with differences in the absolute values depending on the applied method. Linear measurements are affected by the operator and choice of reference points; however, by evaluating the average variations of the entire structure surfaces, local variations should be minimized. The evaluation of the average variations with the second method offers the advantage of a rapid visual representation of these variations.

Toxics or Lures? Biological and Behavioral Effects of Plant Essential Oils on Tephritidae Fruit Flies.

The family Tephritidae (Diptera) includes species that are highly invasive and harmful to crops. Due to globalization, international trade, and human displacement, their spread is continuously increasing. Unfortunately, the control of tephritid flies is still closely linked to the use of synthetic insecticides, which are responsible for detrimental effects on the environment and human health. Recently, research is looking for alternative and more eco-friendly tools to be adopted in Integrated Pest Management (IPM) programs. In this regard, essential oils (EOs) and their main compounds represent a promising alternative to chemical insecticides. EOs are made up of phytoconstituents formed from the secondary metabolism of many plants and can act as attractants or toxics, depending on the dose. Because of this unique characteristic, EOs and their main constituents are promising tools that can be used both in Sterile Insect Technique (SIT) programs and in the "lure and kill" technique, exploiting the attractiveness of the product in the former case and its toxicity in the latter. In this article, current knowledge on the biological and behavioral effects of EOs and their main constituents on tephritid fruit flies is reviewed, mainly focusing on species belonging to the Anastrepha, Bactrocera, Ceratitis, and Zeugodacus genera. The mechanisms of action of EOs, their real-world applications, and challenges related to their use in IPM are critically discussed.

Burkholderia cenocepacia H111 Produces a Water-Insoluble Exopolysaccharide in Biofilm: Structural Determination and Molecular Modelling.

Biofilms are a multicellular way of life, where bacterial cells are close together and embedded in a hydrated macromolecular matrix which offers a number of advantages to the cells. Extracellular polysaccharides play an important role in matrix setup and maintenance. A water-insoluble polysaccharide was isolated and purified from the biofilm produced by Burkholderia cenocepacia strain H111, a cystic fibrosis pathogen. Its composition and glycosidic linkages were determined using Gas-Liquid Chromatography-Mass Spectrometry (GLC-MS) on appropriate carbohydrate derivatives while its complete structure was unraveled by 1D and 2D NMR spectroscopy in deuterated sodium hydroxide (NaOD) aqueous solutions. All the collected data demonstrated the following repeating unit for the water-insoluble B. cenocepacia biofilm polysaccharide: [3)-α-d-Galp-(1→3)-α-d-Glcp-(1→3)-α-d-Galp-(1→3)-α-d-Manp-(1→]n Molecular modelling was used, coupled with NMR Nuclear Overhauser Effect (NOE) data, to obtain information about local structural motifs which could give hints about the polysaccharide insolubility. Both modelling and NMR data pointed at restricted dynamics of local conformations which were ascribed to the presence of inter-residue hydrogen bonds and to steric restrictions. In addition, the good correlation between NOE data and calculated interatomic distances by molecular dynamics simulations validated potential energy functions used for calculations.

Multi-technique microscopy investigation on bacterial biofilm matrices: a study on Klebsiella pneumoniae clinical strains.

Biofilms are communities of bacteria living embedded in a highly hydrated matrix composed of polysaccharides, proteins, and extracellular DNA. This life style confers numerous advantages to bacteria including protection against external threats. However, they also contribute to increase bacterial resistance against antimicrobials, an issue particularly relevant in dangerous infections. Due to the complexity of the matrix, few information is present in the literature on details of its architecture including the spatial distribution of the macromolecular components which might give hints on the way the biofilm scaffold is built up by bacteria. In this study, we investigated the possibility to combine well-established microbiological procedures with advanced microscopies to get information on composition and distribution of the macromolecular components of biofilm matrices. To this, confocal microscopy, diffraction-limited infrared (IR) spectral imaging, and atomic force microscopy (AFM) were used to explore biofilm produced by a clinical strain of Klebsiella pneumoniae. IR imaging permitted to have clues on how the biofilm grows and spreads on surfaces, and the local distribution of the components within it. Through the analysis of the pure component spectra, it was possible to assess the chemical and structural composition of the saccaridic matrix, confirming the data obtained by NMR. It was also possible to follow the time course of biofilm from 6 up to 48 h when the biofilm grew into a 3-dimensional multi-layered structure, characteristic of colonies of bacteria linked together by a complex matrix. In addition, nanoFTIR and AFM investigations allowed the estimation of biofilm growth in the vertical direction and the morphological analysis of bacterial colonies at different time points and the evaluation of the chemical composition at the nanoscale.

Should we fear direct oral anticoagulants more than vitamin K antagonists in simple single tooth extraction? A prospective comparative study.

OBJECTIVES: The aim of this prospective comparative clinical study was to evaluate the effect of oral anticoagulants on peri- and post-operative bleeding during simple single tooth extractions, comparing patients in treatment with vitamin K antagonists (VKAs) and patients assuming direct oral anticoagulants (DOACs). MATERIALS AND METHODS: Patients under oral anticoagulant therapy needing dental extraction were eligible for entering the study; patients were enrolled following inclusion and exclusion criteria and divided into VKAs and DOAC group according to the anticoagulation therapy. Included patients underwent a simple single dental extraction with elevators and forceps with a maximum surgical time of 15 minutes, without anticoagulation therapy discontinuation. All participants were assessed pre-operatively, during surgery, 30 min minutes and 7 days after surgery. Biological complications were registered and post-extraction bleeding was clinically defined according to Iwabuchi classification. Parametric and non-parametric tests were used to evaluate the variables between the groups. RESULTS: Sixty-five patients per group were enrolled and 130 teeth were extracted. The two groups were comparable for pre-, peri-, and post-operative variables. Only 1 patient of DOAC group and 2 patients for VKA group needed medical evaluation for post-extractive bleeding. No statistically significant difference resulted in post-operative bleeding events between the groups (p = 0.425). CONCLUSIONS: DOAC and VKA patients showed the same incidence of bleeding complications after simple single tooth extraction. Bleeding events were not statistically significant and not clinically relevant. CLINICAL RELEVANCE: Patients assuming DOACs can be treated similarly to patients in VKAs therapy with INR index between 2 and 3. Non-ceasing of DOAC therapy seems to be appropriate for simple single dental extractions.

Fluorescence and NMR spectroscopy together with molecular simulations reveal amphiphilic characteristics of a Burkholderia biofilm exopolysaccharide.

Biofilms are a collective mode of bacterial life in which a self-produced matrix confines cells in close proximity to each other. Biofilms confer many advantages, including protection from chemicals (including antibiotics), entrapment of useful extracellular enzymes and nutrients, as well as opportunities for efficient recycling of molecules from dead cells. Biofilm matrices are aqueous gel-like structures composed of polysaccharides, proteins, and DNA stabilized by intermolecular interactions that may include non-polar connections. Recently, polysaccharides extracted from biofilms produced by species of the Burkholderia cepacia complex were shown to possess clusters of rhamnose, a 6-deoxy sugar with non-polar characteristics. Molecular dynamics simulations are well suited to characterizing the structure and dynamics of polysaccharides, but only relatively few such studies exist of their interaction with non-polar molecules. Here we report an investigation into the hydrophobic properties of the exopolysaccharide produced by Burkholderia multivorans strain C1576. Fluorescence experiments with two hydrophobic fluorescent probes established that this polysaccharide complexes hydrophobic species, and NMR experiments confirmed these interactions. Molecular simulations to model the hydrodynamics of the polysaccharide and the interaction with guest species revealed a very flexible, amphiphilic carbohydrate chain that has frequent dynamic interactions with apolar molecules; both hexane and a long-chain fatty acid belonging to the quorum-sensing system of B. multivorans were tested. A possible role of the non-polar domains of the exopolysaccharide in facilitating the diffusion of aliphatic species toward specific targets within the biofilm aqueous matrix is proposed.

The spent culture supernatant of Pseudomonas syringae contains azelaic acid.

BACKGROUND: Pseudomonas syringae pv. actinidiae (PSA) is an emerging kiwifruit bacterial pathogen which since 2008 has caused considerable losses. No quorum sensing (QS) signaling molecule has yet been reported from PSA and the aim of this study was to identify possible intercellular signals produced by PSA. RESULTS: A secreted metabolome analysis resulted in the identification of 83 putative compounds, one of them was the nine carbon saturated dicarboxylic acid called azelaic acid. Azelaic acid, which is a nine-carbon (C9) saturated dicarboxylic acid, has been reported in plants as a mobile signal that primes systemic defenses. In addition, its structure,(which is associated with fatty acid biosynthesis) is similar to other known bacterial QS signals like the Diffusible Signal Facor (DSF). For these reason it could be acting as s signal molecule. Analytical and structural studies by NMR spectroscopy confirmed that in PSA spent supernatants azelaic acid was present. Quantification studies further revealed that 20 µg/L of were present and was also found in the spent supernatants of several other P. syringae pathovars. The RNAseq transcriptome study however did not determine whether azelaic acid could behave as a QS molecule. CONCLUSIONS: This study reports of the possible natural biosynthesis of azelaic acid by bacteria. The production of azelaic acid by P. syringae pathovars can be associated with plant-bacteria signaling.

Influence of Bacterial Biofilm Polysaccharide Structure on Interactions with Antimicrobial Peptides: A Study on Klebsiella pneumoniae.

Balneotherapy is a clinically effective complementary approach in the treatment of low-grade inflammation- and stress-related pathologies. The biological mechanisms by which immersion in mineral-medicinal water and the application of mud alleviate symptoms of several pathologies are still not completely understood, but it is known that neuroendocrine and immunological responses­including both humoral and cell-mediated immunity­to balneotherapy are involved in these mechanisms of effectiveness; leading to anti-inflammatory, analgesic, antioxidant, chondroprotective, and anabolic effects together with neuroendocrine-immune regulation in different conditions. Hormesis can play a critical role in all these biological effects and mechanisms of effectiveness. The hormetic effects of balneotherapy can be related to non-specific factors such as heat­which induces the heat shock response, and therefore the synthesis and release of heat shock proteins­and also to specific biochemical components such as hydrogen sulfide (H2S) in sulfurous water and radon in radioactive water. Results from several investigations suggest that the beneficial effects of balneotherapy and hydrotherapy are consistent with the concept of hormesis, and thus support a role for hormesis in hydrothermal treatments.

Biofilms produced by Burkholderia cenocepacia: influence of media and solid supports on composition of matrix exopolysaccharides.

Bacteria usually grow forming biofilms, which are communities of cells embedded in a self-produced dynamic polymeric matrix, characterized by a complex three-dimensional structure. The matrix holds cells together and above a surface, and eventually releases them, resulting in colonization of other surfaces. Although exopolysaccharides (EPOLs) are important components of the matrix, determination of their structure is usually performed on samples produced in non-biofilm conditions, or indirectly through genetic studies. Among the Burkholderia cepacia complex species, Burkholderia cenocepacia is an important pathogen in cystic fibrosis (CF) patients and is generally more aggressive than other species. In the present investigation, B. cenocepacia strain BTS2, a CF isolate, was grown in biofilm mode on glass slides and cellulose membranes, using five growth media, one of which mimics the nutritional content of CF sputum. The structure of the matrix EPOLs was determined by 1H-NMR spectroscopy, while visualization of the biofilms on glass slides was obtained by means of confocal laser microscopy, phase-contrast microscopy and atomic force microscopy. The results confirmed that the type of EPOLs biosynthesized depends both on the medium used and on the type of support, and showed that mucoid conditions do not always lead to significant biofilm production, while bacteria in a non-mucoid state can still form biofilm containing EPOLs.

New aspects of the structure and mode of action of the human cathelicidin LL-37 revealed by the intrinsic probe p-cyanophenylalanine.

The human cathelicidin peptide LL-37 is an important effector of our innate immune system and contributes to host defence with direct antimicrobial activity and immunomodulatory properties, and by stimulating wound healing. Its sequence has evolved to confer specific structural characteristics that strongly affect these biological activities, and differentiate it from orthologues of other primate species. In the present paper we report a detailed study of the folding and self-assembly of this peptide in comparison with rhesus monkey peptide RL-37, taking into account the different stages of its trajectory from bulk solution to contact with, and insertion into, biological membranes. Phenylalanine residues in different positions throughout the native sequences of LL-37 and RL-37 were systematically replaced with the non-invasive fluorescent and IR probe p-cyanophenylalanine. Steady-state and time-resolved fluorescence studies showed that LL-37, in contrast to RL-37, forms oligomers with a loose hydrophobic core in physiological solutions, which persist in the presence of biological membranes. Fourier transform IR and surface plasmon resonance studies also indicated different modes of interaction for LL-37 and RL-37 with anionic and neutral membranes. This correlated with a distinctly different mode of bacterial membrane permeabilization, as determined using a flow cytometric method involving impermeant fluorescent dyes linked to polymers of defined sizes.

Managing patients taking novel oral anticoagulants (NOAs) in dentistry: a discussion paper on clinical implications.

BACKGROUND: The aim of this paper is to contribute to the discussion on how to approach patients taking new orally administered anticoagulants (NOAs) dabigatran etexilate (a direct thrombin inhibitor), rivaroxaban and apixaban (factor Xa inhibitors), before, during and after dental treatment in light of the more recent knowledges. DISCUSSION: In dentistry and oral surgery, the major concerns in treatment of patients taking direct thrombin inhibitors and factor Xa inhibitors is the risk of haemorrhage and the absence of a specific reversal agent. The degree of renal function, the complexity of the surgical procedure and the patient's risk of bleeding due to other concomitant causes, are the most important factors to consider during surgical dental treatment of patients taking NOAs. For patients requiring simple dental extraction or minor oral surgery procedures, interruption of NOA is not generally necessary, while an higher control of bleeding and discontinuation of the drug (at least 24 h) should be requested before invasive surgical procedures, depending on renal functionality. The clinician has to consider that the number of patients taking NOAs is rapidly increasing. Since available data are not sufficient to establish an evidence-based dental management, the dentist must use caution and attention when treating patients taking dabigatran, rivaroxaban and apixaban.

Lethal and sublethal effects of carlina oxide on Tetranychus urticae (Acari: Tetranychidae) and Neoseiulus californicus (Acari: Phytoseiidae).

BACKGROUND: Tetranychus urticae Koch, is a polyphagous and damaging pest, presenting several resistant populations worldwide. Among new and more environmentally friendly control tools, botanical pesticides represent a valuable alternative to synthetic ones within integrated pest management strategies. Accordingly, we investigated the lethal and sublethal effects of carlina oxide isolated from Carlina acaulis (Asteraceae) roots on T. urticae and its natural enemy, the predatory mite, Neoseiulus californicus (McGregor). RESULTS: Carlina oxide (98.7% pure compound) was used for acaricidal tests on eggs, nymphs, and adult females of T. urticae (concentrations of 312.5, 625, 1250, 2500 and 5000 µL L-1 ), and eggs and females of N. californicus (1250 and 5000 µL L-1 on eggs and females, respectively). Behavioral two-choice tests were also conducted on phytoseiid females. Carlina oxide toxicity was higher on T. urticae females than nymphs (median lethal dose 1145 and 1825 µL L-1 , respectively), whereas egg mortality and mean hatching time were significantly affected by all tested concentrations. A decreasing daily oviposition rate for T. urticae was recorded with concentrations ranging from 625 to 5000 µL L-1 , whereas negative effects on the population growth rate were recorded only with the three higher concentrations (1250, 2500 and 5000 µL L-1 ). No toxic effect on N. californicus females was found, but a strong repellent activity lasting for 48 h from application was recorded. CONCLUSION: Carlina oxide reduced longevity and fecundity of T. urticae adults, but not of N. californicus. This selective property allows us to propose it as a novel active ingredient of ecofriendly acaricides for T. urticae management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Lethal and sublethal effects of synthetic and bioinsecticides toward the invasive ambrosia beetle Xylosandrus compactus.

BACKGROUND: Exotic ambrosia beetles are emerging widespread pests of several wild and managed trees and shrubs. Xylosandrus compactus (Eichhoff) is one of the most invasive species causing damage to a broad range of host plants. Little information is available on its control, including the impact of insecticides. Bioassays were conducted to evaluate the potential of four bioinsecticides and seven synthetic insecticides in controlling X. compactus. Beetle mortality and sublethal effects on tunneling, cultivation of the mutualist fungus and reproduction were assessed. RESULTS: Concentration-mortality curves were determined for all tested insecticides. Lambda-cyhalothrin was the most toxic insecticide, showing the lowest estimated 90% and 50% lethal concentrations (LC90 and LC50 ), followed by deltamethrin and thiamethoxam. Acetamiprid caused the highest levels of mortality and brood size reduction under extended laboratory conditions. Moreover, acetamiprid, thiamethoxam and lambda-cyhalothrin caused the greatest mortality and, together with deltamethrin, strongly affected progeny occurrence inside infested galleries and beetle brood size. Among the bioinsecticides, pyrethrins significantly affected beetle survival under laboratory conditions, but not brood size in extended laboratory bioassays. Some of the tested insecticides had significant lethal and sublethal effects only when beetles were exposed to fresher residues, highlighting differences in toxicity persistence. CONCLUSION: This study provides first baseline toxicity data for synthetic insecticides and bioinsecticides with different modes of action and origin toward X. compactus, and the first evidence that several insecticides can cause multiple sublethal effects on this pest. These findings can help in building suitable integrated pest management packages against this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Bep gene cluster in Burkholderia cenocepacia H111 codes for a water-insoluble exopolysaccharide essential for biofilm formation.

Burkholderia cenocepacia is an opportunistic pathogen isolated from cystic fibrosis patients where it causes infections that are extremely difficult to treat with antibiotics, and sometimes have a fatal outcome. Biofilm is a virulence trait of B. cenocepacia, and is associated with infection persistence and increased tolerance to antibiotics. In biofilms exopolysaccharides have an important role, conferring mechanical stability and antibiotic tolerance. Two different exopolysaccharides were isolated from B. cenocepacia H111 biofilms: a water-soluble polysaccharide rich in rhamnose and containing an L-Man residue, and a water-insoluble polymer made of glucose, galactose and mannose. In the present work, the product encoded by B. cenocepacia H111 bepA-L gene cluster was identified as the water-insoluble exopolysaccharide, using mutant strains and NMR spectroscopy of the purified polysaccharides. It was also demonstrated that the B. cenocepacia H111 wild type strain produces the water-insoluble exopolysaccharide in pellicles, thus underlining its potential importance in in vivo infections.

Microscopy and modelling investigations on the morphology of the biofilm exopolysaccharide produced by Burkholderia multivorans strain C1576.

Bacteria form very often biofilms where they embed in a self-synthesized matrix exhibiting a gel-like appearance. Matrices offer several advantages, including defence against external threats and the easiness of intercellular communication. In infections, biofilm formation enhances bacteria resistance against antimicrobials, causing serious clinical problems for patients' treatments. Biofilm matrices are composed of proteins, extracellular DNA, and polysaccharides, the latter being the major responsible for matrix architecture. The repeating unit of the biofilm polysaccharide synthesized by Burkholderia multivorans strain C1576 contains two mannoses and two sequentially linked rhamnoses, one of them 50 % methylated on C-3. Rhamnose, a 6-deoxysugar, has lower polarity than other common monosaccharides and its methylation further reduces polarity. This suggests a possible role of this polysaccharide in the biofilm matrix; in fact, computer modelling and atomic force microscopy studies evidenced intra- and inter-molecular non-polar interactions both within polysaccharides and with aliphatic molecules. In this paper, the polysaccharide three-dimensional morphology was investigated using atomic force microscopy in both solid and solution states. Independent evidence of the polymer conformation was obtained by transmission electron microscopy which confirmed the formation of globular compact structures. Finally, data from computer dynamic simulations were used to model the three-dimensional structure.

Characterisation of a new cell wall teichoic acid produced by Listeria innocua ZM39 and analysis of its biosynthesis genes.

Listeria innocua is genetically closely related to the foodborne human pathogen Listeria monocytogenes. However, as most L. innocua strains are non-pathogenic, it has been proposed as a surrogate organism for determining the efficacy of antimicrobial strategies against L. monocytogenes. Teichoic acids are one of the three major cell wall components of Listeria, along with the peptidoglycan backbone and cell wall-associated proteins. The polymeric teichoic acids make up the majority of cell wall carbohydrates; the type of teichoic acids directly attached to the peptidoglycan are termed wall teichoic acids (WTAs). WTAs play vital physiological roles, are important virulence factors, antigenic determinants, and phage-binding ligands. The structures of the various WTAs of L. monocytogenes are well known, whereas those of L. innocua are not. In the present study, the WTA structure of L. innocua ZM39 was determined mainly by 1D and 2D NMR spectroscopy and it was found to be the following: [→4)-[α-D-GlcpNAc-(1→3)]-ß-D-GlcpNAc-(1→4)-D-Rbo-(1P→]n This structure is new with respect to all currently known Listeria WTAs and it shares structural similarities with type II WTA serovar 6a. In addition, the genome of strain L. innocua ZM39 was sequenced and the majority of putative WTA synthesis genes were identified.

Impact of Super-High Density Olive Orchard Management System on Soil Free-Living and Plant-Parasitic Nematodes in Central and South Italy.

The soil nematode community plays an important role in ecosystem services. The objective of this study was to assess the effect of Super-high density (SHD) olive orchards on the nematode community in five sites with different soils, climates, and cultivars. At each site, the SHD management system was compared to the adjacent olive orchard traditional (TRAD) system, in which the same soil management and phytosanitary measures were applied. Soil management was assessed by total organic carbon content (TOC), while the soil nematode community was evaluated using the nematode taxa abundances and soil nematode indicators. TOC was significantly decreased in the SHD olive orchard system compared to TRAD in the sites characterized by conventional tillage and mineral fertilization. The two-way ANOSIM analysis on nematode abundance showed no difference between the two olive management methods, instead showing only a significant difference per site mainly due to variabilities in plant-parasitic nematode assemblage. However, a negative impact of SHD management was evident in environments stressed by summer droughts and conventional tillage: the ratio of obligate plant-parasites to bacterivores and fungivores (Pp/(B+F)) was significantly higher in SHD than in the TRAD olive orchard system, and the prey-to-predator θ mass ratio showed the lowest values in the sites under organic fertilization or green manure. The canonical correspondence analysis showed that the free-living nematodes were only slightly affected by SHD olive orchards; instead, the presence of plant-parasitic nematodes families such as Telotylenchidae, Paratylenchidae, Meloidogynidae, and Criconematidae was favored, in comparison to Longidoridae, Heteroderidae, and Pratylenchidae.