Revista Argentina De Microbiologia 

About: Revista Argentina De Microbiologia is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Medicine & Biology. It has an ISSN identifier of 0325-7541. It is also open access. Over the lifetime, 1661 publications have been published receiving 12182 citations.

Effects of temperature, water activity and incubation time on fungal growth and aflatoxin B1 production by toxinogenic Aspergillus flavus isolates on sorghum seeds.

Abstract: Sorghum, which is consumed in Tunisia as human food, suffers from severe colonization by several toxigenic fungi and contamination by mycotoxins. The Tunisian climate is characterized by high temperature and humidity that stimulates mold proliferation and mycotoxin accumulation in foodstuffs. This study investigated the effects of temperature (15, 25 and 37°C), water activity (aw, between 0.85 and 0.99) and incubation time (7, 14, 21 and 28 d) on fungal growth and aflatoxin B1 (AFB1) production by three Aspergillus flavus isolates (8, 10 and 14) inoculated on sorghum grains. The Baranyi model was applied to identify the limits of growth and mycotoxin production. Maximum diameter growth rates were observed at 0.99 a(w) at 37°C for two of the isolates. The minimum aw needed for mycelial growth was 0.91 at 25 and 37°C. At 15°C, only isolate 8 grew at 0.99 a(w). Aflatoxin B1 accumulation could be avoided by storing sorghum at low water activity levels (≤0.91 a(w)). Aflatoxin production was not observed at 15°C. This is the first work on the effects of water activity and temperature on A. flavus growth and AFB1 production by A. flavus isolates on sorghum grains.

Bioprospection of marine microorganisms: biotechnological applications and methods

Abstract: Environmental microorganisms constitute an almost inexhaustible reserve of genetic and functional diversity, accumulated during millions of years of adaptive evolution to various selective pressures. In particular, the extent of microbial biodiversity in marine habitats seems to grow larger as new techniques emerge to measure it. This has resulted in novel and more complex approaches for the screening of molecules and activities of biotechnological interest in these environments. In this review, we explore the different partially overlapping biotechnological fields that make use of microorganisms and we describe the different marine habitats that are particularly attractive for bioprospection. In addition, we review the methodological approaches currently used for microbial bioprospection, from the traditional cultivation techniques to state of the art metagenomic approaches, with emphasis in the marine environment.

Azotobacter chroococcum as a potentially useful bacterial biofertilizer for cotton (Gossypium hirsutum): Effect in reducing N fertilization.

Abstract: The aim of this research was to evaluate whether the application of two plant growth-promoting (rhizo)bacteria might reduce nitrogen fertilization doses in cotton. We used strains Azotobacter chroococcum AC1 and AC10 for their proven ability to promote seed germination and cotton growth. These microorganisms were characterized by their plant growth-promoting activities. Then, we conducted a glasshouse study to evaluate the plant growth promoting ability of these strains with reduced doses of urea fertilization in cotton. Results revealed that both strains are capable of fixing nitrogen, solubilizing phosphorus, synthesizing indole compounds and producing hydrolytic enzymes. After 12 weeks, the glasshouse experiment showed that cotton growth was positively influenced due to bacterial inoculation with respect to chemical fertilization. Notably, we observed that microbial inoculation further influenced plant biomass (p<0.05) than nitrogen content. Co-inoculation, interestingly, exhibited a greater beneficial effect on plant growth parameters compared to single inoculation. Moreover, similar results without significant statistical differences were observed among bacterial co-inoculation plus 50% urea and 100% fertilization. These findings suggest that co-inoculation of A. chroococcum strains allow to reduce nitrogen fertilization doses up to 50% on cotton growth. Our results showed that inoculation with AC1 and AC10 represents a viable alternative to improve cotton growth while decreasing the N fertilizer dose and allows to alleviate the environmental deterioration related to N pollution.

Species distribution and susceptibility profile of yeasts isolated from blood cultures: results of a multicenter active laboratory-based surveillance study in Argentina

Abstract: The Mycology Department of the Instituto Nacional de Enfermedades Infecciosas "Dr. C. Malbran", conducted the Second National Multicenter Survey on Fungemia due to Yeasts in Argentina. The aim was to obtain updated data of the frequency of the causative species encountered and their in vitro susceptibility to seven antifungal agents. Yeast species were identified by micromorphological and biochemical studies. Antifungal susceptibility testing was performed by the reference microdilution method E.Def 7.1 of the European Committee on Antibiotic Susceptibility Testing (EUCAST). A total of 461 viable yeasts were identified. The most frequent species were: Candida albicans (38.4 %), Candida parapsilosis (26 %), Candida tropicalis (15.4 %) and Candida glabrata (4.3 %). Other uncommon species, such as Candida viswanathii (0.6 %), Candida haemulonii (0.4 %), Candida inconspicua (0.2 %) and Candida fermentati (0.2 %) were also isolated. Among the Candida spp., 5.4 % and 1.6 % were resistant to fluconazole and voriconazole, respectively. Itraconazole and caspofungin were the most efficient agents against all Candida spp. tested (MIC 8 mg/l), 75 % of Trichosporon spp., and 100 % of Rhodotorula spp., Geotrichum candidum, Saccharomyces cerevisiae. The global percentage of mortality was 20 %. The presence of uncommon species reinforces the need for performing continuous laboratory surveillance in order to monitor possible changes, not only in the epidemiological distribution of species, but also in the resistance to antifungal drugs.

Bacillus thuringiensis: generalidades.Un acercamiento a su empleo en el biocontrol de insectos lepidópteros que son plagas agrícolas

Abstract: Resumen es: Bacillus thuringiensis es el insecticida biologico mas aplicado en el mundo y se utiliza para controlar diversos insectos que afectan la agricultura, la ...