This study used both microscopic and biochemical analyses to investigate the possible defense responses induced by acibenzolar-S-methyl (ASM) and potassium phosphite (Phi) in mango plants inoculated with Ceratocystis fimbriata. Disease development was evaluated in the stems of inoculated mango plants and these were examined using fluorescence and light microscopy. High-performance liquid chromatography (HPLC) was used to quantify secondary metabolites in the stem sections. Spraying the plants with ASM and Phi reduced internal necrosis and disease development. The ASM and Phi induced many microscopic defense responses in the stem tissues against C. fimbriata infection. HPLC analysis revealed that the concentrations of two alkaloids (theobromine and 7-methylxanthine) and 10 phenolic compounds (catechin, epicatechin, epigallocatechin, gallic acid, myricetin, p-coumaric acid, p-hydroxybenzoic acid, phloridzin, sinapinic acid, and salicylhydroxamic acid) were higher in the stem tissues of plants sprayed with ASM or Phi than in inoculated control treatment. The concentrations of phenolic compounds were higher in the stem tissues of inoculated plants than in noninoculated plants, while the inverse was observed for alkaloids. Higher concentrations of secondary metabolites in the stem tissues were detected in the early stages of fungal infection, especially in plants treated with inducers. Taken together, the results from the present study clearly support the concept that the phenylpropanoid pathway in the stem tissues of mango plants infected by C. fimbriata can be induced by ASM and Phi.

Mango wilt, caused by Ceratocystis fimbriata, is one of the most important diseases affecting mango yields in Brazil. Information regarding the infection process of C. fimbriata in the stem tissues of mango from different cultivars and the basis of host resistance to the pathogen is rare in the literature. Thus, the objective of the study was to investigate how infection by two isolates of C. fimbriata can be affected by mango cultivar-specific mechanisms of resistance. Disease progress on the inoculated stem tissues of the mango cultivars was evaluated and stem sections were obtained from the site of inoculation and prepared for histopathological observations using light microscopy. The factors mango cultivars and C. fimbriata isolates and their interaction were significant for all measures of disease development. Plants from the cultivars Espada, Haden and Palmer inoculated with isolates of C. fimbriata were more susceptible, whereas plants from the cultivars Tommy and Ub a were moderately resistant and resistant, respectively. Histopathologically, fungal isolates apparently massively colonized the stem tissues of plants from the susceptible cultivars Espada, Haden and Palmer, starting from the collenchyma and moving in the direction of the cortical parenchyma, xylem vessels and pith parenchyma. By contrast, on stem tissues of plants from the resistant cultivars Tommy Atkins and Ub a, most of the cells reacted to C. fimbriata infection by accumulating amorphous material. The results from the present study strongly indicated the importance of phenolic compounds for mango cultivar resistance against infection by Brazilian C. fimbriata isolates.

objectIve. The aim of this study was to evaluate the criteria used in clinical practice to triage patients who are candidates for ICU admission. Methods. This was a prospective cohort study conducted at a tertiary hospital. Patients were assessed for their need for ICU admission and ranked by priority into groups 1, 2, 3 and 4 (highest priority 1, lowest priority 4) and these groups were compared. results. The sample comprised 359 patients with a median age of 66 years (53.2-75.0). Median APACHE II score was 23 (18-30). The ICU granted 70.4% of requests for ICU beds. Patients who were refused admission to the ICU were older, 66.2±16.1 vs. 61.9±15.2 years (p= 0.02), and fewer priority 1 patients were refused ICU beds; 23.8% vs. 39.1% of requests refused (p=0.01). The opposite was observed with priorities 3 and 4. Priority 3 and 4 patients were older, scored higher on the prognostic scale and the organ dysfunction scale and had a higher bed refusal rate. Patients in priority groups 3 and 4 had higher in-ICU mortality rates when compared to priority 1 and 2 patients: 86.7% vs. 31.3% (p<0.001). conclusIon. Age, prognostic scores and organ dysfunction scores were all greater among priority 3 and 4 patients and were related to refusal of ICU admission. Patients refused admission to the ICU had higher mortality rates and mortality remained higher among priority 3 and 4 patients even when they were admitted to the ICU.

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This study investigated the effect of silicon (Si) on the potentiation of rice resistance against leaf scald at the microscopic level. Rice plants ('Primavera') were grown in a nutrient solution containing 0 (-Si) or 2 mM (+Si) Si. The foliar Si concentration of the +Si plants (3.6 dag/kg) increased in comparison with the -Si plants (0.3 dag/kg). An X-ray microanalysis revealed that the leaf tissue of +Si plants infected with Microdochium oryzae had higher peaks and deposition of insoluble Si than that of -Si plants. The high foliar Si concentration for the +Si plants reduced the expansion of leaf scald lesions. Scanning electron microscopy revealed that fungal hyphae and appressorium-like structures of M. oryzae were more abundant in the leaf surface of -Si plants relative to +Si plants. At both histopathological and ultrastructural levels, fungal hyphae grew abundantly into the leaf tissue of -Si plants. By contrast, rice cell walls were rarely degraded and fungal hyphae were often surrounded by amorphous granular material in the leaf tissue of +Si plants. Conidiophores emerged from stomata 36 h after fungal penetration, and conidia were noticed inside the leaf tissue of the -Si plants in great abundance. The collective results of the present study showed a high concentration and deposition of Si and a considerable deposition of phenolic-like compounds in the leaf tissue of +Si plants. These results indicate that the potentiation of the phenylpropanoid pathway in these plants supplied with Si was favorable for the increase in rice resistance to leaf scald.

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This study was designed to characterize and describe host cell responses of stem tissue to mango wilt disease caused by the fungus Ceratocystis fimbriata in Brazil. Disease progress was followed, through time, in inoculated stems for two cultivars, 'Ubá' (field resistant) and 'Haden' (field susceptible). Stem sections from inoculated areas were examined using fluorescence light microscopy and transmission and scanning electron microscopy, coupled with energy-dispersive X-ray microanalysis. Tissues from Ubá colonized by C. fimbriata had stronger autofluorescence than those from Haden. The X-ray microanalysis revealed that the tissues of Ubá had higher levels of insoluble sulfur and calcium than those of Haden. Scanning electron microscopy revealed that fungal hyphae, chlamydospores (aleurioconidia), and perithecia-like structures of C. fimbriata were more abundant in Haden relative to Ubá. At the ultrastructural level, pathogen hyphae had grown into the degraded walls of parenchyma, fiber cells, and xylem vessels in the tissue of Haden. However, in Ubá, plant cell walls were rarely degraded and hyphae were often surrounded by dense, amorphous granular materials and hyphae appeared to have died. Taken together, the results of this study characterize the susceptible and resistant basal cell responses of mango stem tissue to infection by C. fimbriata.

ABSTRACT. Glomerella leaf spot (GLS) is an important disease of apple plants, and the use of the algal polysaccharide ulvan represents a new technology for its control. This study aimed to verify whether the defense mechanisms involved in cultivar-specific and ulvan-induced plant resistance to GLS are associated with changes in the activities of peroxidase and β-1,3-glucanase. Seedlings were first sprayed with ulvan or water and then inoculated with Colletotrichum gloeosporioides 6 days later. The disease severity was recorded daily on both young and old leaves up to 10 days after inoculation, and the enzyme activities were monitored from 24 to 72h after inoculation (HAI). Although the young leaves were more susceptible to GLS, ulvan reduced approximately 66% of the disease severity in both of the leaf age groups. Additionally, the cultivar-specific and ulvan-induced resistance was associated with enhanced peroxidase activity at 24 and 72 HAI, respectively. Both the resistant and susceptible seedlings exhibited similar glucanase activities.Keywords: Colletotrichum gloeosporioides, Malus domestica, Ulva sp., induction resistance, peroxidase, glucanase.Resistências cultivar-específica e induzida por ulvana à mancha foliar de Glomerella em macieira são associadas com aumento da atividade de peroxidases RESUMO. Mancha foliar de Glomerella (MFG) é uma doença importante da macieira e o uso do polissacarídeo algal ulvana representa uma nova tecnologia para o seu controle. Este estudo teve como objetivo verificar se os mecanismos de defesa envolvidos na resistência de planta cultivar-específica e induzida por ulvana a MFG estão associados com mudanças na atividade de peroxidase e β-1,3-glucanase. Plântulas foram primeiro pulverizadas com ulvana ou água e então inoculadas com Colletotrichum gloeosporioides 6 dias mais tarde. A severidade da doença foi registrada diariamente em ambas folhas jovens e velhas até 10 dias após a inoculação. Atividade enzimática foi monitorada de 24 a 72h após a inoculação (HAI). Embora, folhas jovens foram mais suscetíveis a MFG, a ulvana reduziu aproximadamente 66% da severidade da doença em ambos grupos etários de folhas. Adicionalmente a resistência cultivar-específica ou induzida por ulvana foi associada com um aumento da atividade de peroxidase às 24 e 72 HAI, respectivamente. Ambas plântulas resistentes e suscetíveis exibiram atividade similar de glucanase.