Aislamiento e identificación de microorganismos amilolíticos y tolerantes a cianuro de efluentes de la industria almidonera

El cultivo de mandioca en la Provincia de Misiones aporta la mayor parte de la producción a nivel nacional. Parte de la misma es destinada a la obtención de fécula, actividad que genera efluentes industriales con una elevada carga de materia orgánica y compuestos cianogénicos. Esto constituye una problemática a nivel ambiental y la biorremediación se presenta como una alternativa para la reducción de estos residuos, ya que se basa en la degradación del contaminante utilizando los microorganismos presentes en la matriz contaminada. El objetivo de este trabajo fue aislar microorganismos con capacidad para degradar almidón y tolerantes a cianuro a partir de efluentes de una industria almidonera. Fueron aisladas 93 cepas bacterianas y 15 de ellas fueron preseleccionadas mediante determinación cualitativa de actividad amilolítica. Utilizando el gen 16S rDNA para la identificación molecular, se determinó que algunos de estos aislamientos pertenecen a los géneros Pseudomonas, Acinetobacter y Proteus. Esas cepas se cultivaron en medio mínimo con distintas concentraciones cianuro y se logró determinar que una de ellas posee tanto la actividad amilolítica como la tolerancia a cianuro, ambas características deseables para biorremediación de efluentes de la industria almidonera.

Proteomic insight on the polychlorinated biphenyl degrading mechanism of Pleurotus pulmonarius LBM 105

White-rot fungi are well known bioremediation agents capable of removing recalcitrant xenobiotics. However, the molecular mechanism involved in this process is not well understood. The aim of the present study was to compare the proteomic profiles of Pleurotus pulmonarius LBM 105 in presence and absence of a mixture of polychlorinated biphenyls. Cultures of the fungus were spiked with a mixture of Aroclors and cultivated for 28 days. This strain achieved a peak of PCBs-removal of 65.50 ± 8.09% after 21 days. The ecotoxicological assays showed a toxicity reduction of 46.47%. Based on these findings, a proteomic study was carried out and it was proven that the oxidative metabolism was highly affected. Two proteins that have a function at the transcriptional level and related to the oxidative metabolism, the glyceraldehyde-3-phosphate dehydrogenase and the basal transcription factor 3, presented an increase in their quantity in PCBs presence. Several oxidases and reductases were highly induced, presenting the short chain reductases, aldo/keto reductases, laccases and versatile peroxidases as the enzymes with the most notorious changes. These results indicate a complex response of the fungal metabolism towards these pollutants, which includes a transcriptional response to the oxidative stress and a modification of the intra- and extra-cellular enzymatic profile.

Secretomic analysis of cheap enzymatic cocktails of Aspergillus niger LBM 134 grown on cassava bagasse and sugarcane bagasse

Currently, agroindustrial wastes are little used for generating value-added products; hence, their use of these waste to produce enzymatic cocktails for the conversion of lignocellulosic biomass to fermentable sugars is a very interesting alternative in the second-generation bioethanol process. The Ascomycota fungus Aspergillus niger LBM 134 produces hydrolytic enzymes in large proportions. In this work, A. niger LBM 134 was grown on sugarcane and cassava bagasses under optimized conditions. To identify the extracellular enzymes involved in the degradation of these agroindustrial wastes, the secretomes of the culture supernatants of the fungus were analyzed and validated by biochemical assays of the enzymatic activities. A. niger LBM 134 secreted higher quantities of xylanases and accessory hemicellulases when it grew on sugarcane bagasse, whereas more cellulases, amylases, and pectinases were secreted when it grew on cassava bagasse. These findings suggest two promising enzyme cocktails for the hydrolysis of lignocellulose carbohydrate polymers to fermentable sugars. These bioinformatic analysis were functional validates through enzymatic biochemical assays that confirm the biotechnological potential of A. niger LBM 134 for the bioconversion of hemicellulosic substrates such as sugarcane and cassava bagasses.

Trichoderma spp. from Misiones, Argentina: effective fungi to promote plant growth of the regional crop Ilex paraguariensis St. Hil

Ilex paraguariensis St. Hil (yerba mate) is an important crop in the north of Argentina, mainly in Misiones province. The application of Trichoderma as a biocontroller and biofertilizer can replace or reduce the use of agrochemicals, decreasing the negative ecological impact. In this research, we evaluated in vitro and in vivo antagonistic and plant growth promoting (PGP) properties of Trichoderma species isolated from different regions of Misiones province. Dual culture assays of Trichoderma against phytopathogenic fungi associated with yerba mate showed that T. stilbohypoxyli LBM 120 was the most effective antagonist, inhibiting in more than 75% all phytopathogen growth. Trichoderma atroviride LBM 112 and T. stilbohypoxyli LBM 120 were positive on endoglucanase, protease, chitinase, siderophore production, and phosphate solubilisation showed the best biological control agents and PGP properties. The PGP properties of Trichoderma spp. evaluated in vivo on yerba mate seedlings showed that T. atroviride LBM 112, T. stilbohypoxyli LBM 120, and T. koningiopsis LBM 219 enhanced plant dry weight over 47% in total and 24% in the aerial part. Moreover, T. koningiopsis LBM 219 increased root dry weight 25% in contrast with in vitro controls. In conclusion, native Trichoderma strains could be a sustainable solution to improve yerba mate yield.

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.