RESUMEN
From April to June 2010, mango fruits (Mangifera indica L.) (cv. Tommy Atkins) showing post-harvest anthracnose symptoms were collected during a survey conducted in São Francisco Valley, northeastern Brazil. Fruits affected by anthracnose showed sunken, prominent, dark brown to black decay spots. Small pieces (4 to 5 mm) of necrotic tissues were surface sterilized for 1 min in 1.5% NaOCl, washed twice with sterile distilled water, and plated onto potato dextrose agar (PDA) amended with 0.5 g liter-1 streptomycin sulfate. Plates were incubated at 25°C in the dark for 5 to 7 days and colonies that were morphologically similar to species of Colletotrichum were transferred to PDA (1). Identification was made using morphological characteristics and phylogenetic analysis. Two isolates (CMM 4101 and CMM 4102) presented colonies that had white aerial mycelia and orange conidial mass, varying between colorless and pale orange in reverse. Conidia were hyaline, cylindrical, and aseptate 14.52 (10.40 to 20.20) µm long and 4.90 (3.80 to 6.50) µm wide, length/width ratio = 3.0. Mycelial growth rate was 5.20 mm per day at 25°C. Morphological and cultural characterizations were consistent with the description of Colletotrichum karstii (3). PCR amplification by universal primers (ITS1/ITS4) and DNA sequencing of the internal transcribed spacer (ITS1-5.8S-ITS2 rRNA gene cluster) were conducted to confirm the identifications. Analysis of representative sequences (GenBank Accession Nos. HM585409 and HM585406) suggested that the isolated pathogen was C. karstii. Using published ITS data for C. karstii (3), a phylogenetic analysis was made via Bayesian inference, which shows that the isolated fungi belong to the C. karstii clade. Sequences of the isolates obtained in this study were deposited in GenBank (KC295235 and KC295236), and cultures were deposited in the Culture Collection of Phytopathogenic Fungi of the Universidade Federal Rural de Pernambuco (CMM, Recife, Brazil). Pathogenicity tests were conducted with the C. karstii strains on mango fruits cv. Tommy Atkins. Mycelial plugs taken from the margin of actively growing colonies (PDA) of each isolate were applied in shallow wounds (0.4 cm in diameter) at the medium region of the each fruit. PDA discs without fungal growing were used as controls. Inoculated fruits were placed in plastic containers lined with paper towels wetted in distilled water. The containers were partially sealed with plastic bags to maintain high humidity and incubated at 25°C in the dark. The plastic bags and paper towels were removed after 24 h, and fruits were kept at the same temperature. The experiment was arranged in a completely randomized design with four replicates per treatment (isolate) and four fruits per replicate. Typical anthracnose symptoms were observed after 10 days in mango fruits. C. karstii was successfully reisolated from symptomatic mango fruits to fulfill Koch's postulates. C. karstii was previously described from Orchidaceae in southwest China and the United States (2,3). To our knowledge, this is the first report of C. karstii causing mango anthracnose in Brazil and worldwide. References: (1) U. Damm et al. Stud. Mycol. 73:1, 2012. (2) I. Jadrane et al. Plant Dis. 96:1227, 2012. (3) Yang et al. Cryptogamie Mycol. 32:229, 2011.
RESUMEN
Canine leishmaniosis (CanL) caused by the protozoan parasite Leishmania infantum is a chronic systemic disease that is endemic in certain parts of the world. The domestic dog is the most important reservoir of L. infantum and is the main source of infection for other animals and for the human population. The aim of this study was to evaluate and compare the level of expression of genes encoding particular cytokines (interleukin [IL]-12, interferon [IFN]-γ, IL-2 and IL-4) in different tissues and organs of 53 adult dogs with or without clinical signs of leishmaniosis and after treatment for the disease. Asymptomatic dogs showed high expression of genes encoding IL-4 in blood leucocytes and of genes encoding IL-12 and IL-2 in lymph nodes. Blood leucocytes from symptomatic dogs had a mixed Th1 and Th2 cytokine gene expression profile, but lymph nodes from these animals had dominant IL-2 and IFN-γ gene expression, while bone marrow appeared to be unresponsive. The predominance of IL-4 gene expression in the blood of asymptomatic dogs may favour parasite replication, while the balance between Th1 and Th2 cytokine gene expression in the blood of symptomatic dogs may be important in reducing parasite replication and delaying the dissemination of Leishmania to other organs. The drugs used to treat CanL do not completely eliminate the parasite, so the high expression of the gene encoding IL-4 in blood leucocytes and the high expression of IL-12 and IL-4 mRNA in lymph nodes may reflect the persistence of residual Leishmania amastigotes. L. infantum appears able to regulate the host immune response in order to ensure its survival, but also to prevent the host from succumbing to infection. This guarantees its transmission and the completion of its life cycle.
