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Early reports accounted for two main genotypes of Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis, placing the single isolate EM-90 apart from the prototypic LF-89 and related isolates. In this study, we provide evidence that, contrary to what has been supposed, the EM-90-like isolates are highly prevalent and disseminated across Chilean marine farms. Molecular analysis of 507 P. salmonis field isolates derived from main rearing areas, diverse hosts and collected over 6 years, revealed that nearly 50% of the entire collection were indeed typed as EM-90-like. Interestingly, these isolates showed a marked host preference, being recovered exclusively from Atlantic salmon (Salmo salar) samples. Although both strains produce undistinguishable pathological outcomes, differences regarding growth kinetics and susceptibility to the antibiotics and bactericidal action of serum could be identified. In sum, our results allow to conclude that the EM-90-like isolates represent an epidemiologically relevant group in the current situation of piscirickettsiosis. Based on the consistency between genotype and phenotype exhibited by this strain, we point out the need for genotypic studies that may be as important for the Chilean salmon industry as the continuous surveillance of antimicrobial susceptibility patterns.

Botrytis cinerea CCg425 contains a 33-nm isometric mycovirus whose genome is a 6.8-kb double-stranded RNA (dsRNA) molecule. Virulence bioassays, performed by direct plug mycelial inoculation on bean plant leaves, showed that B. cinerea CCg425 displays less fungal aggressivity than B. cinerea CKg54, a virulent fungal strain that is not infected by dsRNA mycoviruses. B. cinerea CCg425 also showed lower laccase activity and conidiation rate than B. cinerea CKg54. Furthermore, infection of B. cinerea CKg54 with viral particles purified from B. cinerea CCg425 resulted in diminished virulence of the infected fungus. Collectively, our results indicate that mycovirus infection confers hypovirulence to the fungal host.

Salmonella enterica serotype Typhimurium is a food-borne pathogen that also selectively grows in tumours and functionally decreases P-glycoprotein (P-gp), a multidrug resistance transporter. Here we report that the Salmonella type III secretion effector, SipA, is responsible for P-gp modulation through a pathway involving caspase-3. Mimicking the ability of Salmonella to reverse multidrug resistance, we constructed a gold nanoparticle system packaged with a SipA corona, and found this bacterial mimic not only accumulates in tumours but also reduces P-gp at a SipA dose significantly lower than free SipA. Moreover, the Salmonella nanoparticle mimic suppresses tumour growth with a concomitant reduction in P-gp when used with an existing chemotherapeutic drug (that is, doxorubicin). On the basis of our finding that the SipA Salmonella effector is fundamental for functionally decreasing P-gp, we engineered a nanoparticle mimic that both overcomes multidrug resistance in cancer cells and increases tumour sensitivity to conventional chemotherapeutics.

Blossom blight is a destructive disease of plums (Prunus salicina) when humid and temperate weather conditions occur in Chile. Disease incidence ranging from 4 to 53% has been observed. Symptoms include light brown petal necrosis, starting as light brown mottles or V-shaped necrosis at the margins of the petals, progressing to the stamen and pistils. In this study, the etiology of blossom blight of plums was determined. High- and low-sporulating isolates of Botrytis were obtained consistently from blighted blossoms and apparently healthy flowers of plums. Based on colony morphology, conidial production and molecular phylogenetic analysis, these high- and low-sporulating isolates were identified as B. cinerea and B. prunorum sp. nov., respectively. Phylogenetic analysis of the genes glyceraldehyde 3-phosphate dehydrogenase (G3PDH), heat-shock protein 60 (HSP60), and DNA-dependent RNA polymerase subunit II (RPB2) grouped B. prunorum isolates in a single cluster, distantly from B. cinerea and other Botrytis species. The phylogenetic analysis of necrosis and ethylene-inducing protein (NEP1 and NEP2) genes corroborated these results. Analysis of the internal transcribed spacer region and large-subunit (26S) ribosomal DNA and detection of Boty and Flipper transposable elements, were not useful to differentiate between these Botrytis species. Both species were pathogenic on plum flowers and the fruit of plums, apples, and kiwifruits. However, B. prunorum was less virulent than B. cinerea. These pathogens were re-isolated from inoculated and diseased tissues; thus, Koch's postulates were fulfilled, confirming its role in blossom blight of plums. B. cinerea was predominant, suggesting that B. prunorum may play a secondary role in the epidemiology of blossom blight in plums in Chile. This study clearly demonstrated that the etiology of blossom blight of plums is caused by B. cinerea and B. prunorum, which constitute a species complex living in sympatry on plums and possibly on other stone fruit trees.

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Brassicaceae are an outstanding source of bioactive compounds such as ascorbic acid, polyphenols, essential minerals, isothiocyanates and their precursors, glucosinolates (GSL). Recently, GSL gained great attention because of the health promoting properties of their hydrolysis products: isothiocyanates. Among them, sulforaphane (SFN) became the most attractive one owing to its remarkable health-promoting properties. SFN may prevent different types of cancer and has the ability to improve hypertensive states, to prevent type 2 diabetes–induced cardiomyopathy, and to protect against gastric ulcer. SFN may also help in schizophrenia treatment, and recently it was proposed that SFN has potential to help those who struggle with obesity. The mechanism underlying the health-promoting effect of SFN relates to its indirect action at cellular level by inducing antioxidant and Phase II detoxifying enzymes through the activation of transcription nuclear factor (erythroid-derived 2)-like (Nrf2). The effect of SFN on immune response is generating scientific interest, because of its bioavailability, which is much higher than other phytochemicals, and its capacity to induce Nrf2 target genes. Clinical trials suggest that sulforaphane produces favorable results in cases where pharmaceutical products fail. This article provides a revision about the relationship between sulforaphane and immune response in different diseases. Special attention is given to clinical trials related with immune system disorders.