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Several types of (mostly) blue-green glass beads from Iron-Age archaeological sites in Central Italy were studied using a range of spectroscopic techniques: portable X-Ray Fluorescence spectrometry, Fibre Optics Reflectance Spectroscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectrometry, micro-Raman spectroscopy and Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Complementary information was gathered from each technique and discussed in the frame of the archaeological typology of the objects. The systematic evaluation of the results allowed us to draw some conclusions on the raw materials employed for primary production and to highlight some provenance indicators in the glass. Some of the beads found in the Iron Age (IA) contexts were preliminarily attributed to the Final Bronze Age (FBA) production based on their typology, and the compositional data obtained in this work confirmed that they were low magnesium high potassium (LMHK) glass, typical of FBA in the Italian peninsula. Other beads were assigned to low magnesium glass (LMG) or high magnesium glass (HMG), thus giving further information on the fluxing agents employed in the Early Iron Age (EIA) and beyond. Colour variations among the beads reflected their chemical composition, with different bead typologies coloured in a specific way. In some instances, it was possible to establish different origins for the colouring raw materials. The provenance of the samples was difficult to place, but the chemical evidence suggested a subdivision within the raw glass used to produce the beads: for one set of samples, a local origin of the glass could be hypothesised, whereas several production sites in the Near East were suggested for most of the beads considered in this study. Some preliminary clues for the local working of imported glass were also highlighted for one typological group.

The provenance of raw lapis lazuli used since the Neolithic Age for the realization of carved artefacts can be pivoting for the reconstruction of ancient trade routes. The role of main provider of this material in ancient times is generally attributed to the Badakhshan quarries (Afghanistan), although other deposits could have been exploited as well since antiquity. The systematic multi-technique analysis of lapis lazuli rocks coming from four known source areas (located in present-day Afghanistan, Tajikistan, Siberia and Chile) has led in the last years to the compilation of a protocol for provenance determination. The protocol is based on differences in the physical–chemical properties measured with non-invasive techniques (Ion Beam Analysis (IBA)), making it suitable also for precious ancient artefacts. In this work, 10 new reference samples from the Mogok quarry (Myanmar), previously subjected to a complete petrographic and mineralogical characterization, have been analysed employing $$\mu$$ μ -PIXE (Proton Induced X-ray Emission) and $$\mu$$ μ -IBIL (Ion Beam Induced Luminescence) techniques. The subdivision of Myanmar samples into three groups, previously suggested, is corroborated by diopside trace elements concentrations. The results also allow to include Myanmar as a new provenance in the analytical protocol, indicating that provenance markers such as presence/absence of wollastonite, altered pyrites and Sr content are still valid to discriminate also the Myanmar lapis lazuli from Chilean or Siberian ones. New weaker markers (Zn content in diopside, Se and Cu contents in pyrite) are proposed for the discrimination of Myanmar from Afghan or Tajik provenances; however, from the analysis it arose the need of investigating new mineral phases with IBA to find strong markers for a definitive discrimination with samples from Southwest Asia.

Background Several semi-automatic software are available for the three-dimensional reconstruction of the airway from DICOM files. The aim of this study was to evaluate the accuracy of the segmentation of the upper airway testing four free source and one commercially available semi-automatic software. A total of 20 cone-beam computed tomography (CBCT) were selected to perform semi-automatic segmentation of the upper airway. The software tested were Invesalius, ITK-Snap, Dolphin 3D, 3D Slicer and Seg3D. The same upper airway models were manually segmented (Mimics software) and set as the gold standard (GS) reference of the investigation. A specific 3D imaging technology was used to perform the superimposition between the upper airway model obtained with semi-automatic software and the GS model, and to perform the surface-to-surface matching analysis. The accuracy of semi-automatic segmentation was evaluated calculating the volumetric mean differences (mean bias and limits of agreement) and the percentage of matching of the upper airway models compared to the manual segmentation (GS). Qualitative assessments were performed using color-coded maps. All data were statistically analyzed for software comparisons. Results Statistically significant differences were found in the volumetric dimensions of the upper airway models and in the matching percentage among the tested software (p 3; matching = 90.05%) followed by ITK-Snap (mean bias = − 2.52 cm3; matching = 84.44%), Seg 3D (mean bias = 3.21 cm3, matching = 87.36%), 3D Slicer (mean bias = − 4.77 cm3; matching = 82.08%) and Dolphin 3D (difference mean = − 6.06 cm3; matching = 78.26%). According to the color-coded map, the dis-matched area was mainly located at the most anterior nasal region of the airway. Volumetric data showed excellent inter-software reliability (GS vs semi-automatic software), with coefficient values ranging from 0.904 to 0.993, confirming proportional equivalence with manual segmentation. Conclusion Despite the excellent inter-software reliability, different semi-automatic segmentation algorithms could generate different patterns of inaccuracy error (underestimation/overestimation) of the upper airway models. Thus, is unreasonable to expect volumetric agreement among different software packages for the 3D rendering of the upper airway anatomy.

The archaeological site of Adulis lays on the Red Sea Coast of Eritrea and during Late antiquity played a significant role in interregional commerce among the Mediterranean, the Red Sea and the Indian Ocean coasts. Contacts with the Eastern Mediterranean, Arabian Peninsula and the Sasanian world have been attested from different classes of pottery that were brought to light from on-going excavations at the site. Transport vessels have attracted particular attention as they testify the extent of trades and exchange networks. Transport vessels were coated by organic materials to seal porosity and make them suitable to transport different liquids and/or food. The characterisation of coating materials helped shedding light on their function, and support the attribution to different classes of transport vessels found in the Indian Ocean and Red Sea worlds. Here, the characterisation of the organic lining detected on a set of samples identified as Late Roman Amphora 1 is discussed. Results from the chemical analyses, performed preliminarily by FT-IR and then by GC–MS, revealed that bitumen was used for lining the jars, thus leading to set the classification of the amphorae within the wide class of the so- called Torpedo jars. By overcoming the question of typological complexity posed from macroscopic examination of the sherds, the chemical investigation contributed here crucial information for the interpretation of past trading in the Indian Ocean. The research gave clues to broaden the distribution of the Torpedo jars to Adulis, giving an unexpected insight into the trading routes of the past.

Changes applied to the Prostate cancer (PCa) histopathology grading, where patients with cribriform patterns (CP) may be categorized as grade group 2 and could hypothetically be surveilled. However, CP has been associated with worse oncological outcomes. The aim of our study is to systematically review and meta-analyze the available evidence on CP in PCa patients.This analysis was registered on PROSPERO (CRD42022298473). We performed a systematic literature search of PubMed, EMBASE and Scopus using Medical Subject Headings (MeSH) indexes, keyword searches, and publication types until December 2021. The search terms included: "prostate", "prostate cancer" and "cribriform". We also searched reference lists of relevant articles. Eligible studies included published journal articles that provided quantitative data on the association between cribriform patterns at radical prostatectomy and the presence of extra-prostatic extension (EPE), seminal vesicle invasion (SVI), positive surgical margins (PSM), biochemical recurrence (BCR) or cancer specific mortality (CSM).Overall, 31 studies were included for the quantitative analysis. All articles have been published during a span of 11 years (2011-2022) with a mean month of follow-up of 62.87 months. The mean quality of these studies, assessed with the Newcastle Ottawa Scale was 6.27. We demonstrated that CP was associated with greater risk of EPE (odds ratio [OR] 1.96; P 0.0001), SVI (OR: 2.89; p 0.01), and PSM (OR: 1.88; p 0.0007). Our analyses showed that CP was associated with greater risk of BCR (hazard ratio [HR]: 2.14; p 0.01) and of CSM (HR: 3.30, p 0.01).The presence of CP is associated with adverse pathology at radical prostatectomy and worse biochemical recurrence and cancer specific mortality. These results highlight the importance of a better pathologic report of CP to advise clinician for a strict follow-up in PCa patients.

Purpose In this study, we aimed to identify prognostic factors of cancer mortality in patients who received radical cystectomy and to identify genomic alterations in a sub-cohort of patients with locally advanced (pT3-4) and/or positive lymph nodes bladder cancer (BC). Methods We collected 101 BC samples from 2010 to 2018 who previously received radical cystectomy. Immunohistochemical slides were evaluated for PPAR, cAMP, IMP3, Ki67, CDK4, POU5F1, Cyclin E and MDM2, p65, CD3, CD4, CD8, CD20, CD68, CD163, FOXP3, PD-1 and PD-L1 expression. We calculated a prognostic score (PS) based on the positivity to PD-1, PD-L1 and of cAMP (final score ranging from 0 to 3). DNA of each sample have been used for sequencing by NGS in a sub-cohort of 6 patients with locally advanced (pT3-4) and/or positive lymph nodes BC. Results PD-1 + (HR [hazard ratio] 2.59; p = 0.04), PD-L1+ (HR = 6.46; p + (HR 3.04; p = 0.02) were independent predictors of cancer-specific mortality (CSM). Increase of PS (score = 0 as reference) was associated with CSM, 0.81 (p = 0.80), 4.72 (p = 0.01) and 10.51 (p Conclusion BC exhibited heterogenous protein expression and variable genomic features. Identification of expression of PD-1, PD-L1 and cAMP could help in predicting oncological outcomes.

Objectives: The purpose of this study was to evaluate mandibular asymmetry in youngsters with posterior unilateral crossbite (PUXB), through cone-beam computed tomography and reverse engineering technique, before and after rapid maxillary expansion (RME) treatment. Materials and methods: Forty cone-beam computed tomography (CBCT) images were obtained from all patients at two time points, namely T0 acquired before the placement of a Hyrax expander and T1 after appliance removal. The CBCT scans were segmented and volume rendered into a surface there-dimensional (3D) mesh model. Thereafter, mandibular models were digitally registered by using a “best-fit” algorithm. Surface and volumetric changes, between T0 and T1, were compared by using Student’s t tests. Results: A slight increase of 0.45 cm3 of the total mandibular volume was found at T1 when compared with T0 (p < 0.001). The mandibular hemi-volume on the crossbite side (CB) was slightly smaller than the non-crossbite side both at T0 and T1. However, the mean differences of hemi-volume from the CB (crossbite) and non-CB side between T0 and T1 show a decrease of 0.26 cm3 (p < 0.001). Findings for the surface-to-surface deviation analysis demonstrated a fine percentage of matching at T0 which slightly improved at T1 (p < 0.001). Conclusions: Youngsters affected by PUXB showed a very slight and not statistically significant volumetric and morphological asymmetry between CB side and non-CB side at T0. However, the change in mean differences of 0.26 cm cannot be considered clinically relevant. Clinical relevance: Mandibles in young PUXB patients exhibit only a very mild mandibular asymmetry. Although the statistically significant mean change found right after RME removal cannot be considered clinically relevant, a more consistent sample and a longer follow-up could be of interest in explaining the short-term findings.

The objective of this study was to evaluate the accuracy of dental models prototyped via entry-level liquid crystal display (LCD) 3D printers.Identical prototyped models were generated from a master digital file testing two entry-level LCD-based 3D printers and using one professional-grade 3D printer as gold standard (GS), with 50-µm and 100-µm layer thickness. Each 3D-printed model was scanned, and a specific 3D technology was used to perform surface-based superimposition and deviation analysis to evaluate trueness and precision. The distances between surface points of two superimposed models were converted to root mean square (RMS) and statistically analyzed.The RMS values detected were significantly higher in dental models prototyped with entry-level compared to the SLA printer (p 0.001), in terms of trueness (50 µm: GS 0.075 mm, LCD1 0.192 mm, LCD2 0.179 mm; 100 µm: GS 0.066 mm, LCD1 0.209 mm, LCD2 0.199 mm) and precision (50 µm: GS 0.028 mm, LCD1 0.075 mm, LCD2 0.085 mm; 100 µm: GS 0.039 mm, LCD1 0.096 mm, LCD2 0.101 mm). No significant differences were found between the values of RMS of both entry-level 3D printers (p 0.05). Layer thickness did not affect either the trueness or precision of the 3D-printed models (p 0.05).Entry-level LCD-based 3D printers are not as accurate as professional-grade 3D printer, but still close to orthodontics clinical threshold values.Clinicians should evaluate the intended application of 3D-printed orthodontic models before using entry-level 3D printers.

To compare incidental fragility fractures in psoriatic arthritis (PsA) patients with matched controls from a university hospital.Consecutive PsA patients were matched (age and sex) with controls (1:2). Follow-up began at index date, defined as the date of PsA diagnosis for cases and their respective controls, until the last hospital visit, death or the end of the study (31 December 2017). Electronic medical records were reviewed for osteoporotic fractures. Incidence rates per 100,000 persons-years (PY) of distinct types of fractures after index dates were calculated and compared between groups. A multivariate Cox regression analysis was performed to investigate determinants of fractures.Ninety-two PsA patients and 184 controls were included. No difference was found in the overall fracture incidence rate per 100,000 PY between PsA and controls (1020 95% CI 510-1930, vs 870 95% CI 520-1390, p = 0.36). Vertebral fractures were numerically more frequent in PsA patients with an incidence rate of 1020 (95% CI 510-1930) per 100,000 PY versus 460 (95% CI 240-920), per 100,000 PY in the control group but it did not reach statistical significance (p = 0.06). In the Cox regression analysis, after adjusting for bisphosphonate use, only age (HR 1.10, 1.05-1.16, p 0.001) and female sex (HR 3.94, 1.11-13.91, p = 0.03) were associated with fractures while PsA diagnosis and use of glucocorticoids were not.In this cohort of PsA patients, no overall increased risk of fractures was found in comparison with matched controls. Key Points • PsA could have different effects on bone, leading to confusing results in bone densitometry readings contributing to the difficulty in establishing the real prevalence of OP in PsA. • Vertebral fractures were more frequent in PsA patients compared to controls, but it did not reach statistical significance. No difference was found in the overall fracture incidence rate.

In the last years, data lakes are emerging as an effective and an efficient support for information and knowledge extraction from a huge amount of highly heterogeneous and quickly changing data sources. Data lake management requires the definition of new techniques, very different from the ones adopted for data warehouses in the past. In this scenario, one of the most challenging issues to address consists in the extraction of topic-guided (i.e., thematic) views from the (very heterogeneous and often unstructured) sources of a data lake. In this paper, we propose a new network-based model to uniformly represent structured, semi-structured and unstructured sources of a data lake. Then, we present a new approach to, at least partially, “structuring” unstructured data. Finally, we define a technique to extract topic-guided views from the sources of a data lake, based on similarity and other semantic relationships among source metadata.

Extracellular polymeric substances (EPSs) possess diversified ecological role, including the cell adhesion to surfaces and cell protection, and are highly involved in the interactions between the bacterial cells and the bulk environments. Interestingly, EPSs find valuable applications in the industrial field, due to their chemical versatility. In this context, Antarctic bacteria have not been given the attention they deserve as producers of EPS molecules and a very limited insight into their EPS production capabilities and biotechnological potential is available in literature to date. Antarctic EPS-producing bacteria are mainly psychrophiles deriving from the marine environments (generally sea-ice and seawater) around the continent, whereas a unique thermophilic bacterium, namely Parageobacillus thermantarcticus strain M1, was isolated from geothermal soil of the crater of Mount Melbourne. This mini-review is aimed at showcasing the current knowledge on EPS-producing Antarctic bacteria and the chemical peculiarities of produced EPSs, highlighting their biotechnological potential and the yet unexplored treasure they represent for biodiscovery.

Anthropogenic impact over the Pasvik River (Arctic Norway) is mainly caused by emissions from runoff from smelter and mine wastes, as well as by domestic sewage from the Russian, Norwegian, and Finnish settlements situated on its catchment area. In this study, sediment samples from sites within the Pasvik River area with different histories of metal input were analyzed for metal contamination and occurrence of metal-resistant bacteria in late spring and summer of 2014. The major differences in microbial and chemical parameters were mostly dependent on local inputs than seasonality. Higher concentrations of metals were generally detected in July rather than May, with inner stations that became particularly enriched in Cr, Ni, Cu, and Zn, but without significant differences. Bacterial resistance to metals, which resulted from viable counts on amended agar plates, was in the order Ni2+> Pb2+>Co2+>Zn2+>Cu2+>Cd2+>Hg2+, with higher values that were generally determined at inner stations. Among a total of 286 bacterial isolates (mainly achieved from Ni- and Pb-amended plates), the 7.2% showed multiresistance at increasing metal concentration (up to 10,000 ppm). Selected multiresistant isolates belonged to the genera Stenotrophomonas, Arthrobacter, and Serratia. Results highlighted that bacteria, rapidly responding to changing conditions, could be considered as true indicators of the harmful effect caused by contaminants on human health and environment and suggested their potential application in bioremediation processes of metal-polluted cold sites.

Over the time, instrument transportability has become more and more important, especially in Cultural Heritage, as often artworks cannot be moved from their site, either because of the size or due to problems with permission issues, or simply because moving them to a laboratory is physically impossible, as e.g. in the case of mural paintings. For this reason, the INFN-CHNet, the network for Cultural Heritage studies of the Italian National Institute of Nuclear Physics (INFN), has developed an XRF scanner for in situ analyses. The instrument is the result of a wide collaboration, where different units of the network have been developing the diverse parts, then merged in a single system. The XRF scanner has been designed to be a four-season and green instrument. The control/acquisition/analysis software has been fully developed by our group, using only open-source software. Other strong points of the system are easiness of use, high portability, good performances and ultra-low radiation dispersion, which allows us to use even when the public can be present. It can run both with mains or on batteries, in the latter case with a maximum runtime longer than 10 h. It has a very low cost, when compared to commercial systems with equivalent performances, and easily replaceable components, which makes it accessible for a much wider portion of the interested community. The system has been thought and designed as an open system, suitable for further development/improvements, that can result interesting for non-conventional XRF analysis. The CHNet XRF scanner has proved to be really very well suited for applications in the Cultural Heritage field, as testified by the many recent applications. This paper describes the present version of our instrument and reports on the tests performed to characterise its main features. Fil: Taccetti, F.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Castelli, L.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Czelusniak, C.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Gelli, N.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Mazzinghi, A.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Palla, L.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Ruberto, C.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Censori, C.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Lo Giudice, A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; Italia Fil: Re, A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; Italia Fil: Zafiropulos, D.. Istituto Nazionale di Fisica Nucleare; Italia Fil: Arneodo, F.. New York University Abu Dhab; Emiratos Arabes Unidos Fil: Conicella, V.. New York University Abu Dhab; Emiratos Arabes Unidos Fil: Di Giovanni, A.. New York University Abu Dhab; Emiratos Arabes Unidos Fil: Torres, R.. New York University Abu Dhab; Emiratos Arabes Unidos Fil: Castella, F.. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina Fil: Mastrangelo, Noemi Elisa. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gallegos, D.. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina Fil: Tascon, Marcos. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentina Fil: Marte, F.. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; Argentina Fil: Giuntini, L.. Università degli Studi di Firenze; Italia

Objective To assess and compare volumetric and shape changes of the orbital cavity in patients treated with tooth-borne (TB) and bone-borne (BB) rapid maxillary expansion (RME). Study design Forty adolescents with bilateral maxillary cross-bite received tooth-borne (TB group = 20; mean age 14.27 ± 1.36 years) or bone-borne (BB group = 20; mean age of 14.62 ± 1.45 years) maxillary expander. Cone-beam computed tomography (CBCT) were taken before treatment (T1) and 6-month after the expander activation (T2). Volumetric and shape changes of orbital cavities were detected by referring to a specific 3D digital technology involving deviation analysis of T1/T2 CBCT-derived models of pulp chamber. Student’s t tests were used to 1) compare T1 and T2 volumes of orbital cavities in TB and BB groups, 2) compare volumetric changes and the percentage of matching of 3D orbital models (T1-T2) between the two groups. Results Both TB and BB groups showed a slight increase of the orbital volume (0.64 cm3 and 0.77 cm3) (p p p > 0.05). The areas of greater changes were detected in the proximity of the frontozygomatic and frontomaxillary sutures. Conclusion TB-RME and BB-RME would not seem to considerably affect the anatomy or the volume of the orbital cavity in adolescents.

Background Mock-up based approach allows the preview of the aesthetic rehabilitation, however, it is crucial that the mock-up does not differ from the expected aesthetic outcomes. With CAD-CAM technologies, it is possible to directly create mock-ups from virtual planned smile project, with greater accuracy and efficiency compared to the conventional moulded mock-ups. In this study, we investigated the trueness of mock-ups obtained with milling and 3D printing technology and a full digital work-flow system. Methods Ten adults subjects were included and digital smile design/digital wax-up were performed to enhance the aesthetic of maxillary anterior region. Ten milled mock-ups and 10 prototyped mock-ups were obtained from the original .stl file and a digital analysis of trueness was carried out by superimposing the scanned-milled mock-ups and the scanned-prototyped mock-ups to the digital wax-up, according to the surface-to-surface matching technique. Specific linear measurements were performed to investigate and compare the dimensional characteristics of the physical manufactures, the 3D project and the scanned mock-ups. All data were statistically analyzed. A clinical test was also performed to assess the fitting of the final manufacture. Results The prototyped mock-ups showed a significant increment of the transversal measurements (p p p Conclusion Both prototype and milled mock-ups showed a slight dimensional increment comparing to the original 3D project, with milled-mock-ups showing less fitting after clinical tests. Caution must be taken when assessing the trueness of scanned manufacture since an intrinsic error in the system can underestimate the dimensions of the real object.

While several clathrin-independent endocytic processes have been described so far, their biological relevance often remains elusive, especially in pathophysiological contexts such as cancer. In this study, we find that the tumor marker CD166/ALCAM (Activated Leukocyte Cell Adhesion Molecule) is a clathrin-independent cargo. We show that endophilin-A3—but neither A1 nor A2 isoforms—functionally associates with CD166-containing early endocytic carriers and physically interacts with the cargo. Our data further demonstrates that the three endophilin-A isoforms control the uptake of distinct subsets of cargoes. In addition, we provide strong evidence that the construction of endocytic sites from which CD166 is taken up in an endophilin-A3-dependent manner is driven by extracellular galectin-8. Taken together, our data reveal the existence of a previously uncharacterized clathrin-independent endocytic modality, that modulates the abundance of CD166 at the cell surface, and regulates adhesive and migratory properties of cancer cells., How and which cell surface molecules are taken up by clathrin-independent endocytosis is an ongoing area of research. Here, the authors show that the tumor marker CD166 is a clathrin-independent cargo that is taken up by endophilin-A3 and galectin-8, which regulates cancer cell migration.

Porifera dominate vast areas of the Antarctic shelves and are successfully colonized by bacteria. Quorum sensing (QS) is a cell-to-cell communication system based on bacterial population density that, enabling the coordination of group-based behaviour, plays a critical role in the successful colonization of higher organisms, also driving the formation of biofilm for adhesion to surfaces. In this study, the production of N-Acyl homoserine lactones (AHLs), signal molecules involved in the QS mechanism, was examined for 211 Antarctic sponge-associated Gram-negative bacteria. AHL production was screened by using three different AHL biodetection systems, i.e. Agrobacterium tumefaciens pZLR4, Chromobacterium violaceum CV026 and Pseudomonas putida pKR-C12 with optimal sensitivity to moderate-chain (C8–C12), short-chain (C4–C8) and long-chain (≥ C14) AHLs, respectively. 57.8% of tested isolates activated at least one of the monitor systems used and belonged mainly to bacterial genera that are known to be involved in surface colonization by biofilm production. A thin-layer chromatographic assay based on the A. tumefaciens reporter system was utilized to determine the AHL profiles of five selected positive isolates. Visible spots on thin-layer chromatography (TLC) plates were produced by Roseobacter sp. TB60 and Psychrobacter sp. TB67 (both from the sponge, Anoxycalyx joubini). The former probably produced N-(3-oxohexanoyl)-L-homoserine lactone (similar to the standard 3-oxo-C6-HSL), whereas the isolate TB67 produced molecules that were similar to the standard N-butanoyl-homoserine lactone (C4-HSL). The obtained results demonstrated that AHL-based signalling may play a key role in sponge–bacteria interactions also in the Antarctic environment.

The EPS-producing Pseudoalteromonas sp. MER144 was selected among 606 isolates from Antarctic seawater due to its evident slimy appearance on agar plates. The production of EPSs was enhanced by a step-by-step approach varying the carbon source, substrate and NaCl concentrations, temperature, and pH. Optimal conditions for the EPS production resulted at temperature of 4 °C and pH 7, with addition of 2% sucrose (w/v) and 3% NaCl (w/v). EPSs produced under optimal conditions were chemically characterized, resulting in a moderate carbohydrate content (35%), uronic acids (14%), and proteins (12%). Monosaccharide composition was estimated to be Glu:Man:GluN:Ara:GluA:GalA:Gal (1:0.36:0.26:0.06:0.06:0.05:0.03), while the estimated molecular weight was about 250 kDa. The addition of sucrose in the culture medium, by stimulating the EPS production, allowed MER144 to tolerate higher concentrations of mercury and cadmium. This finding was probably dependent on the presence of uronic acids and sulfate groups, which can bind cations, in the extracted EPSs. Monitoring EPS production under optimal conditions at different concentrations of mercury and cadmium revealed that EPS amounts increased at increasing heavy metal concentrations, indicating an adaptation to the stress conditions tested.

Bacterial biofilm production is recognized as a strategy that helps aquatic bacteria in resisting to the presence of several kinds of pollutants, including antibiotics, in the bulk environment. The Pasvik River, located between Norway, Russia and Finland, is a sub-Arctic site polluted by wastes from metallurgic and mining activities. In order to study whether and to what extent bacteria are able to produce biofilms, and to assess whether this physiological characteristic influences their resistance to antibiotics, an investigation was performed on bacteria isolated from water and sediment collected along the Pasvik River course during two surveys (May and July). Bacterial strains were screened for their biofilm production and profiles of susceptibility to antibiotics. Results showed that biofilm formation was a widespread characteristic of the isolates. Most of them were also resistant to several antibiotics, such as ampicillin (100% of the isolates) as well as cefazolin, cefoxitin, ceftriaxone, mezlocillin, nitrofurantoin and sisomicin (90% of the total strains). This study shows a significant association between biofilm formation and antibiotic resistance at inner stations both in water and in sediments in May only. This suggests that in Pasvik River colder temperature may stimulate bacterial aggregation into biofilm and simultaneously decrease bacterial susceptibility to antibiotics; since the occurrence of antibiotic resistance has frequently been linked to the presence of pollutants, this result could represent a strategy of bacterial survival under altered environmental conditions.