Ilex paraguariensis Hosts Root-Trichoderma spp. with Plant-Growth-Promoting Traits: Characterization as Biological Control Agents and Biofertilizers

In this study, the effect of native plant-growth-promoting microorganisms (PGPM) as bio-inoculants was assessed as an alternative to improve Ilex paraguariensis Saint Hilaire growth in the nursery. Fourteen Trichoderma strains isolated from yerba mate roots were evaluated in vitro for their potential as biological control agents (BCA) and PGPM. The PGPM properties were evaluated through the strain's antagonistic activity against three fungal pathogens (Alternaria sp., F. oxysporum, and F. solani) plus the production of extracellular cell-wall-degrading enzymes such as chitinase, β-1,3-glucanase, and cellulase. These results were used to calculate different PGPM indices to select the strains with the optimal properties. Four Trichoderma strains: T. asperelloides LBM193, LBM204, LBM206, and Trichoderma sp. LBM202, were selected based on their indirect and direct PGPM properties used in an inoculation assay on yerba mate plants in greenhouse conditions. A highly significant positive effect of bio-inoculation with these Trichoderma strains was observed in one-year-old yerba mate seedlings. Inoculated plants exhibited a greater height, chlorophyll content, and dry weight than un-inoculated plants; those treated with LBM193 manifested the best results. Yerba mate plants treated with LBM202 exhibited a healthy appearance and were more vigorous, showing potential for biocontrol agent. In conclusion, yerba mate seedlings in the Misiones region were found to have a reservoir of Trichoderma species that increases the yield of this crop in the nursery and protects them from adverse biotic and abiotic agents.

Diagrammatic scale for quantification of severity of white thread blight disease in yerba mate (Ilex paraguariensis Saint Hilaire)

The yerba-mate industry is one of the most important economic activities in Misiones, a province in the northeast of Argentina that is the world's leading producer and exporter of this crop. White thread blight disease caused by Ceratobasidium niltonzousanum affects the cultivation reducing its quality and productivity. Due to the lack of a standardized visual method to quantify the severity of this disease in yerba mate, a diagrammatic scale was developed and validated. Yerba-mate branches were collected in a field in the north of Misiones province, and the actual severity was determined digitally. A six-level scale was developed using the DOSLOG software, based on the Weber-Fechner law. The validation was carried out by twenty raters. One evaluation without the diagrammatic scale and two evaluations with the scale were carried out in 14-day intervals. Accuracy, precision, and reproducibility of the scale were evaluated through linear regressions and correlation analysis, obtaining R2 values ranged between 0.70 and 0.94. Using the diagrammatic scale developed in this work, raters enhanced the accuracy and precision of the estimates, and the repeatability of the scale improved by 94.74%. The scale was appropriate to assess the damage of white thread blight in yerba mate.

Aislamiento e identificación de hongos asociados a Ilex paraguariensis St. Hil

El cultivo de Ilex paraguariensis es importante en el norte de Argentina, principalmente en la provincia de Misiones. En los últimos años se ha observado la presencia de diferentes síntomas de enfermedades causadas por hongos de los cuales no se conoce agente causal, epidemiología y daño económico. En este estudio, se aislaron hongos de hojas de yerba mate que presentaban síntomas visibles de lesiones foliares. Cinco aislados (Alternaria, Colletotrichum, Phoma y Pilidium) fueron seleccionados por sus características micro y macromorfológicas. Estos hongos fueron identificados utilizando un microscopio óptico y claves morfológicas. Se realizaron ensayos de patogenicidad en hojas y en plantas de un año de yerba mate. Los resultados mostraron que Colletotrichum sp. LBM 183 y Phoma sp. LBM 207 son patógenos de hoja de yerba mate capaces de desarrollarse en el tejido. Mientras que Alternaria sp. LBM 186 y Pilidium sp. LBM 208 fueron capaces de enfermar la planta ingresando por la raíz de yerba mate.

Mycobacterium leprae DNA content, cellular and cytokine patterns in skin lesions of leprosy patients undergoing multidrug therapy (MDT)

Skin biopsies from untreated and MDT-treated patients were examined for infiltrating cells and cells producing the cytokines TNF-alpha, IFN-gamma, and IL-1 beta using immunohistochemistry. Biopsy specimens from untreated tuberculoid leprosy patients were characterized by the presence of cells producing TNF-alpha, IFN-gamma, and IL-1 beta and of subepidermal Langerhans cells. These cells were rarely found or completely absent in biopsies of untreated lepromatous leprosy patients, but tended to increase under MDT. In a short-term therapy trial for three months with brodimoprim, dapsone, and rifampicin, 12 patients were monitored by follow-up biopsies. Semiquantitative PCR for mycobacterial DNA revealed two groups of patients: one group in which mycobacterial DNA in follow-up biopsies remained constant and a second group in which a decrease of mycobacterial DNA during therapy was noted. Immunophenotyping in these follow-up biopsies revealed that in the latter group IFN-gamma-positive cells and Langerhans cells were present and gamma delta T cell receptor-positive cells tended to decrease during therapy. In contrast, in patients whose mycobacterial DNA did not change during therapy, these phenotypical manifestations were not observed. We therefore, conclude that assessment of mycobacterial DNA in combination with phenotyping of infiltrating cells and determination of cytokine patterns may be useful tools in establishing criteria for the effectiveness and duration of MDT in patients with leprosy.

Use of a different buffer system in the phenolic glycolipid-I ELISA

By changing the buffer system in the phenolic glycolipid-I (PGL-I) enzyme-linked immunosorbent assay (ELISA) the sensitivity of the test was increased without altering its specificity. Using a Tris-HCl buffer, significant titers of > or = 1:300 were found in 53.1% of the sera in paucibacillary (PB) and 98.0% of the sera in multibacillary (MB) groups of patients. Titer levels were also significantly increased. In the PB group of patients with Tris-HCl, the highest titer detected was 1:1200; in the MB group of patients, 1:76,800. Through this modification of the buffer system a more sensitive test was obtained thereby increasing the detectable level of PGL-I antibodies in both the PB and MB groups of patients.

[Short-term chemotherapy of leprosy using the combination rifampicin + cotrimoxazole + isoniazid]

With the fixed combination RMP + SXT + INH an objective and subjective improvement was obtained within two months, even in severe LL-cases. Treatment resulted in final and relapse-free cure. In the majority of patients the typical erythematous infiltrative oedematous skin processes disappeared within the two months of treatment, in some of them (three of 21) within the six-month follow-up period. Lepromas (15 cases) disappeared in two patients within the two months of treatment. In the sixth month of the follow-up period nine patients were free from lepromas. In another six cases they subsided in the course of the following months. Reactions occurred in 13 patients, in part during treatment, in part during the follow-up period. Three of them were reversal reactions. Chemotherapy was not interrupted. When required, corticosteroids or thalidomide were given in addition. Erythema nodosum leprosum (17 cases) quickly subsided under treatment. Tolerance and compliance were excellent. The subjective minor "side effects" were not specific and cannot clearly be attributed to the medication. The major advantage of the combination RMP + INH + SXT described in this paper lies in the considerably reduced treatment duration (two to four months instead of two years), the rapid disappearance of the symptoms typical of leprosy, the high tolerance, the ease of application as fixed combination and the absence of relapses. So far the patients have been followed up for two years. Through the short treatment duration the cost of treatment is considerably reduced. The new combination allows outpatient treatment and is universally applicable. The patient can maintain his social and professional habits.

A new short-term combination therapy of leprosy

Report on the results with a new therapy with a complex combination (rifampicin + co-trimoxazole + isoniazid) for the treatment of leprosy. High tolerance. Duration of treatment 2 months.

Isoprodian and rifampicin in the treatment of leprosy: a descriptive evaluation of therapy durations in 475 Paraguayan leprosy patients

In Paraguay, the National Leprosy/Tuberculosis Program is based on a combined chemotherapy with isoprodian and rifampicin. The aim of this descriptive study was to investigate the therapy durations used so far in the treatment of 475 leprosy patients and to analyze the criteria responsible for the wide-ranging differences in therapy durations. As initial criteria, the following parameters were identified to have a significant influence on the therapy duration: Patients never treated before or pretreated, clinical classification and initial bacteriological index (BI) value. During therapy, conditions like the attendance and BI decrease/year showed a significant correlation with the therapy duration. Even though the studied criteria did not allow to draw a definite conclusion with regard to an 'ideal' therapy duration, they proved to be reliable, as only 2 patients have relapsed so far.