Culture storage age and fungal re‐isolation from host‐tissue influence Colletotrichum spp. virulence to pepper fruits

Using resistant cultivars is the most sustainable and practical approach against plant diseases. Plant germplasm and breeding lines are selected and assayed against, usually, the most aggressive or virulent strains of a pathogen (e.g., fungus) that causes the disease. However, prolong storage of the pathogen in culture media could affect virulence that, consequently, also influence the outcome of the resistance assay. This study demonstrates that long‐term storage (at least a year) of Colletotrichum truncatum and C. scovillei, causal agents of pepper anthracnose, in potato dextrose agar (PDA) medium decreased the aggressiveness and virulence of the fungus in host‐pepper fruits. However, reintroduction of the pathogen to the host and isolation of the pathogen as the new inoculum, prior to inoculation assays, increased the virulence of the fungi. These findings suggest that re‐inoculation and re‐isolation of Colletotichum truncatum and C. scovillei that have been stored for at least 1 year in PDA medium are necessary when using fungal cultures in pathogenicity and plant resistance assays to achieve desirable, comparable and reliable results.     

Genetic and biochemical investigation on chloral hydrate in vitro and in vivo

Chloral hydrate (CH), a metabolite of trichloroethylene (TCE), was studied in vitro using the D7 diploid strain of Saccharomyces cerevisiae, with and without a mammalian microsomal activation system (S9 fraction), and in vivo by intrasanguineous host-mediated assay (HMA). The in vivo effects on the hepatic microsomal monooxygenase induced by CH in mice pretreated with beta-naphthoflavone (beta-NF) and Naphenobarbital (PB) were also investigated. Chloral hydrate induced a significant increase of mitotic gene conversion in D7 strain both in vivo and in vitro. The enzymatic determinations in mice showed a decrease in aminopyrine N-demethylase (APD) and p-nitroanisole O-demethylase (p-NAD) activities (about 37% and 29% respectively) after one acute dose of CH. Moreover, stability experiments, carried out in the conditions of the liver microsomal assay (LMA), showed an increase of residual activity, after 1 h of preincubation with respect to the control (about 22% and 9% for APD and p-NAD respectively).     

The ABC transporter-encoding gene AFR1 affects the resistance of Cryptococcus neoformans to microglia-mediated antifungal activity by delaying phagosomal maturation

The pathogenic yeast Cryptococcus neoformans has evolved several strategies to survive within phagocytes. Recently, it has been demonstrated that upregulation of the ATP binding cassette transporter-encoding gene antifungal resistance 1 ( AFR1 ) is important not only for determining the resistance of C. neoformans to fluconazole but also in influencing fungal virulence. In the present study, we showed that the fluconazole-resistant AFR1- overexpressing mutant strain was not sensitive to microglia-mediated anticryptococcal activity, as compared with the fluconazole-susceptible isogenic strains, the wild type and the afr1 Δ mutant. Interestingly, although the three strains were phagocytosed to a similar extent, reduced acidification and delayed maturation were observed in phagosomes containing the AFR1 -overexpressing strain with respect to the others. These findings provide the first evidence that upregulation of the AFR1 gene affects C. neoformans –microglia interplay, adding insights to the complexity of cryptococcal virulence and to its unexpected link with azole resistance.     

Mucosal Adjuvant Activity of IL-2 Presenting Spores of Bacillus subtilis in a Murine Model of Helicobacter pylori Vaccination

The endospores of Bacillus subtilis are now widely used as a platform for presentation of heterologous proteins and due to their safety record and high resistance to harsh environmental conditions can be considered as potential vehicles for oral vaccination. In this research we show that recombinant B. subtilis spores presenting a fragment of the Helicobacter acinonychis UreB protein and expressing the ureB gene under vegetative promoter elicit a strong cellular immune response in orally immunized mice when co-administered with spores presenting IL-2. We show for the first time the successful application of two types of recombinant spores, one carrying an antigen and the other an adjuvant, in a single oral immunization.     

The Acoustic Codes: How Animal Sign Processes Create Sound-Topes and Consortia via Conflict Avoidance

In this essay we argue for the possibility to describe the co-presence of species in a community as a consortium built by acoustic codes, using mainly the examples of bird choruses. In this particular case, the consortium is maintained via the sound-tope that different bird species create by singing in a chorus. More generally, the formation of acoustic codes as well as cohesive communicative systems (the consortia) can be seen as a result of plastic adaptational behaviour of the specimen who can solve and avoid conflicts both with conspecifics and with other species in the vicinity. Thus, sign-relations appear to resolve potential conflicts, and as a foundation for symbiotic aggregations. The spatio-temporal configuration of consortia—their chronotope—includes several eco-fields as respective to different functions of the participating organisms. Biological study is combined with a semiotic approach that, as we suggest, should be more often used together to effectively describe ecological processes.     

Fate and Dissemination of Bacillus subtilis Spores in a Murine Model

Bacterial spores are being consumed as probiotics, although little is known about their efficacy or mode of action. As a first step in characterizing spore probiotics, we have studied the persistence and dissemination of Bacillus subtilis spores given orally to mice. Our results have shown that spores do not appear to disseminate across the mucosal surfaces. However, we found that the number of spores excreted in the feces of mice was, in some experiments, larger than the original inoculum. This was an intriguing result and might be explained by germination of a proportion of the spore inoculum in the intestinal tract, followed by limited rounds of cell growth and then sporulation again. This result raises the interesting question of whether it is the spore or the germinated spore that contributes to the probiotic effect of bacterial spores.     

Peripheral Blood Lymphocyte Typing as a Useful Tool to Objectify the Oral Mucosa Patch Test in the Diagnosis of Allergic Contact Mucositis to Nickel

Nickel (Ni) exposure through the intestinal mucosa may cause a hypersensitivity reaction recently defined as allergic contact mucositis (ACM). This condition is identifiable by the oral mucosa patch test (omPT), a qualitative and subjective examination that requires clinical expertise. Our aim was to evaluate if a peripheral blood lymphocyte typing performed before and after the omPT for Ni may be able to objectify this examination for diagnostic purposes. Thirty patients with symptoms referable to the ingestion of Ni-rich foods were subjected to omPT for Ni. Before and after the omPT, each patient underwent blood sampling for the typing of total lymphocytes and their subsets (T, T helper or Th, T cytotoxic or Tc, B, natural killer or NK). Statistical analysis was performed by Student t test and receiver operating characteristic (ROC) curve analysis. According to the omPT outcomes, 18 patients were defined as Ni-sensitive and the remaining 12 as controls. In Ni-sensitive patients, the number of total, T, Th, Tc, and B lymphocytes/μL whole blood increased after the omPT (p?<?0.0001 for the first three, p?=?0.0004 and p?=?0.0001 for the last two lymphocyte types). No omPT-dependent lymphocyte increase was observed in controls. The post/pre omPT cell ratio, especially if calculated for Th lymphocytes, appears to be an effective index for diagnostic purposes (sensitivity?=?100 %, specificity?=?83.3 %, Youden index?=?0.833, area under curve (AUC)?=?0.926, p?<?0.0001). In conclusion, the peripheral blood lymphocyte typing with calculation of post/pre omPT cell ratio has the potential to support the omPT in diagnosing ACM, with the advantage of providing quantitative and objective data.