Every year worldwide some extraordinary wildfires occur, overwhelming suppression capabilities, causing substantial damages, and often resulting in fatalities. Given their increasing frequency, there is a debate about how to address these wildfires with significant social impacts, but there is no agreement upon terminology to describe them. The concept of extreme wildfire event (EWE) has emerged to bring some coherence on this kind of events. It is increasingly used, often as a synonym of other terms related to wildfires of high intensity and size, but its definition remains elusive. The goal of this paper is to go beyond drawing on distinct disciplinary perspectives to develop a holistic view of EWE as a social-ecological phenomenon. Based on literature review and using a transdisciplinary approach, this paper proposes a definition of EWE as a process and an outcome. Considering the lack of a consistent "scale of gravity" to leverage extreme wildfire events such as in natural hazards (e.g., tornados, hurricanes and earthquakes) we present a proposal of wildfire classification with seven categories based on measurable fire spread and behavior parameters and suppression difficulty. The categories 5 to 7 are labeled as EWE.

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A previous analysis showed that Gammaproteobacteria could be the sole recoverable bacteria from surface-sterilized nodules of three wild species of Hedysarum. In this study we extended the analysis to eight Mediterranean native, uninoculated legumes never previously investigated regarding their root-nodule microsymbionts. The structural organization of the nodules was studied by light and electron microscopy, and their bacterial occupants were assessed by combined cultural and molecular approaches. On examination of 100 field-collected nodules, culturable isolates of rhizobia were hardly ever found, whereas over 24 other bacterial taxa were isolated from nodules. None of these nonrhizobial isolates could nodulate the original host when reinoculated in gnotobiotic culture. Despite the inability to culture rhizobial endosymbionts from within the nodules using standard culture media, a direct 16S rRNA gene PCR analysis revealed that most of these nodules contained rhizobia as the predominant population. The presence of nodular endophytes colocalized with rhizobia was verified by immunofluorescence microscopy of nodule sections using an Enterobacter-specific antibody. Hypotheses to explain the nonculturability of rhizobia are presented, and pertinent literature on legume endophytes is discussed.

ObjectivesVaccination against COVID-19 is highly recommended to patients affected by multiple sclerosis (MS); however, the impact of MS disease-modifying therapies (DMTs) on the immune response following vaccination has been only partially investigated. Here, we aimed to elucidate the effect of DMTs on the humoral immune response to mRNA-based anti-SARS-CoV-2 vaccines in MS patients.MethodsWe obtained sera from 912 Sardinian MS patients and 63 healthy controls 30 days after the second dose of BNT162b2 vaccine and tested them for SARS-CoV-2 response using anti-Spike (S) protein-based serology. Previous SARS-CoV-2 infection was assessed by anti-Nucleocapsid (N) serology. Patients were either untreated or undergoing treatment with a total of 13 different DMTs. Differences between treatment groups comprised of at least 10 patients were assessed by generalized linear mixed-effects model. Demographic and clinical data and smoking status were analyzed as additional factors potentially influencing humoral immunity from COVID-19 vaccine.ResultsMS patients treated with natalizumab, teriflunomide, azathioprine, fingolimod, ocrelizumab, and rituximab showed significantly lower humoral responses compared to untreated patients. We did not observe a statistically significant difference in response between patients treated with the other drugs (dimethyl fumarate, interferon, alemtuzumab and glatiramer acetate) and untreated patients. In addition, older age, male sex and active smoking were significantly associated with lower antibody titers against SARS-CoV-2. MS patients previously infected with SARS-CoV-2 had significantly higher humoral responses to vaccine than uninfected patients.ConclusionHumoral response to BNT162b2 is significantly influenced by the specific DMTs followed by patients, as well as by other factors such as previous SARS-CoV-2 infection, age, sex, and smoking status. These results are important to inform targeted strategies to prevent clinically relevant COVID-19 in MS patients.

The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies.Trichomonas vaginalis is a parasitic protozoon responsible for trichomoniasis, one of the most common sexually transmitted diseases in humans, estimated to affect at least 200 million people worldwide (37). Studies carried out with large groups of women suffering from vaginitis showed that T. vaginalis is clinically associated with Mycoplasma hominis (18, 35), a bacterium that, like the protozoon, resides exclusively in the human genital tract. The association is strictly species specific, since is not observed with Ureaplasma urealyticum, another Mollicutes species that is a much more common inhabitant of the human genital tract. The clinical association between the two pathogens has been recently explained by the demonstration of a symbiotic relationship between T. vaginalis and M. hominis (27). More than 90% of T. vaginalis clinical isolates from our collection proved to be infected by M. hominis independent of their geographic origin. Our recent work has allowed us to shed light on some aspects of the phenomenon (28).The presence of endosymbionts in free-living protozoa is frequently described, but it has been never reported in obligate parasitic protozoa. The first example of symbiosis involving a human pathogen was described for Legionella pneumophila, a bacterial pathogen that is responsible for Legionnaire's disease, and Acanthamoeba sp., a free-living opportunistic amoeba (30). The relationship between T. vaginalis and M. hominis is the only one described so far involving two obligate human pathogens. T. vaginalis is responsible for severe vaginitis accompanied by abdominal pain, itching, and foul-smelling discharge (29) and is mainly asymptomatic in men (20). Moreover, trichomoniasis is associated with an enhanced risk of neoplastic transformation in cervical tissues (38) and increased human immunodeficiency virus seroconversion in women (22,31). The mechanisms by which T. vaginalis exerts its pathogenic effects involve adhesion to host cells (1, 2, 19) and the activity of pH-dependent pore-forming proteins (14, 15) and of cytoskeleton-disrupting proteases (16). M. hominis c...