Laura Raiger Iustman

Universidad de Buenos Aires | UBA · Faculty of Exact and Natural Sciences

Actualmente existe una preocupación por desarrollar nuevas herramientas, y mejorar las ya existentes,para la biorremediación de cuerpos de agua o sedimentos contaminados. En este trabajo presentamosuna potencial alternativa para la biorremediación de sedimentos, basada en el uso de celdas decombustible microbianas. Asimismo, presentamos una propues...

Environmental changes and human activities can alter the structure and diversity of aquatic microbial communities. In this work, we analyzed the bacterial community dynamics of an urban stream to understand how these factors affect the composition of river microbial communities. Samples were taken from a stream situated in Buenos Aires, Argentina,...

Brevibacterium linens AE038-8 is an arsenic hyper-tolerant bacterial strain, previously isolated from well water in Tucumán, Argentina. The aim of this study was to characterize this strain regarding its resistance to different stress factors and to evaluate its antiviral activity against Herpes simplex virus type 1 (HSV-1). We found that B. linens...

In Argentina, periurban agriculture is performed by farmers with inadequate training in the use of pesticides and chemical fertilizers, developing horticulture with serious soil deterioration. The aim of this work was to monitor bacterial diversity of a horticultural soil (S) and a reference soil (R) as quality index for the design of future restor...

In Buenos Aires periurban area, horticultural practices are one of the most important activities. Pesticides and fertilisers are used without any control to cover the farmers’ needs, obtaining high crop yields at short terms and modifying soil ecosystem in the long term. The aim of this work was to isolate indigenous strains from periurban horticul...

Environments co-contaminated with heavy metals and hydrocarbons have become an important problem worldwide, especially due to the effect of metals on hydrocarbon degrading microorganisms. Pseudomonas extremaustralis, a bacterium isolated from a pristine pond in Antarctica, showed high capabilities to cope with environmental stress and a very versat...

We investigated for the first time the expression of melanoma cell adhesion molecule (MCAM) and its involvement in the differentiation of 3T3-L1 fibroblasts to adipocytes. We found that MCAM mRNA increased subsequent to the activation of the master regulator of adipogenesis, PPARγ, and this increase was maintained in the mature adipocytes. On the o...

Diesel fuel is one of the most important sources of hydrocarbon contamination worldwide. Its composition consists of a complex mixture of n-alkanes, branched alkanes and aromatic compounds. Hydrocarbon degradation in Pseudomonas species has been mostly studied under aerobic conditions; however, a dynamic spectrum of oxygen availability can be found...

Temperature is one of the most important factors for bacterial growth and development. Cold environments are widely distributed on earth, and psychrotolerant and psychrophilic microorganisms have developed different adaptation strategies to cope with the stress derived from low temperatures. Pseudomonas extremaustralis is an Antarctic bacterium abl...

Up-regulated genes under cold conditions in P. extremaustralis. All genes presented P≤0.05 and Q≤0.05. (Rockhopper software). (DOC)

GO categories in differentially expressed genes. (DOC)

Quantitative Real Time PCR: total RNA was extracted from wild type strain cultures grown at 8°C and 30°C and expression of 5 selected genes between both conditions was comparatively analyzed. Values represent the mean ± SD of three independent experiments. (PDF)

Down-regulated genes under cold conditions in P. extremaustralis. All genes presented P≤0.05 and Q≤0.05 (Rockhopper software). (DOC)

Dot blot representing normalized count for each RNA-seq replicate. Spearman correlation coefficient is shown for each treatment. Replicates with no expression (value of cero) are not shown. (PDF)

Absorption spectrum of leuco and shift base forms of p-rosaniline at 548nm and 420 nm. (PDF)

GC chromatograms obtained from the analysis of culture supernatants of P. extremaustralis grown at 8°C. A. Control LB medium. B. Control LB medium plus pure ethanol. C. Supernatant of P. extremaustralis. (DOC)

The genome of the Antarctic bacterium Pseudomonas extremaustralis was analyzed searching for genes involved in environmental adaptability focusing on anaerobic metabolism, osmoregulation, cold adaptation, exopolysaccharide production and degradation of complex compounds. Experimental evidences demonstrated the functionality of several of these path...

Stressful conditions prevailing in hydrocarbon-contaminated sites influence the diversity, distribution, and activities of microorganisms. Oil bioremediation agents should develop special characteristics to cope with these environments like surfactant production and cellular affinity to hydrocarbons. Additionally, polyhydroxyalkanoate (PHA) accumul...

Adipogenesis is stimulated in 3T3-L1 fibroblasts by a combination of insulin, dexamethasone and isobutylmethylxanthine, IBMX, (I+D+M). Two transcription factors are important for the acquisition of the adipocyte phenotype, C/EBP beta (CCAT enhancer-binding protein beta) and PPAR gamma (peroxisome proliferator-activated receptor gamma). IBMX increas...

Industrial Biotechnology and Applied Microbiology is an optional 128h-course for Chemistry and Biology students at the Faculty of Sciences, University of Buenos Aires, Argentina. This course is usually attended by 25 students, working in teams of two. The curriculum, with 8 lab exercises, includes an oil bioremediation practice covering an insight...

Gas chromatograms of diesel extract from cultures of P. extremaustralis growing in a biofilm and b shaken flasks. White arrows indicate C14, C15, C16, C17 and C21. Grey arrows indicate pristane and phytane. S2 Percentage of residual hydrocarbons in biofilms and shaken flask. Bars represent mean ± standard deviation of triplicates experiments. +PHA...

Pseudomonas extremaustralis 14-3b presents genes involved in the synthesis of different polyhydroxyalkanoates, in tolerance and degradation of pollutants, and in microaerobic metabolism. Several genomic islands were detected. Genetic machinery could contribute to the adaptability to stressful conditions. This is the first genome sequence reported f...

Diesel is a widely distributed pollutant. Bioremediation of this kind of compounds requires the use of microorganisms able to survive and adapt to contaminated environments. Pseudomonas extremaustralis is an Antarctic bacterium with a remarkable survival capability associated to polyhydroxyalkanoates (PHAs) production. This strain was used to inves...

In oil contaminated environments the poor carbon source availability, the presence of toxic compounds like benzene, toluene, and xylene (BTX), and other biotic and abiotic stresses can reduce bacteria viability and consequently, xenobiotic biodegradation. Selection of bacteria with the capability to tolerate and degrade monoaromatic compounds, synt...

To determine whether the stationary sigma factor, sigma(S), influences polyhydroxyalkanoate metabolism in Pseudomonas putida KT2440, an rpoS-negative mutant was constructed to evaluate polyhydroxyalkanoate accumulation and expression of a translational fusion to the promoter region of the genes that code for polyhydroxyalkanoate synthase 1 (phaC1)...

Contradictory results on the effectiveness of energy transfer from the light harvesting complex 2 (LH2) directly to the reaction center (RC) in mutant strains lacking the core light-harvesting complex 1 (LH1) have been obtained with cells of Rhodobacter capsulatus and Rhodobacter sphaeroides. A LH1(-) mutant of Rhodovulum sulfidophilum, named rsLRI...

Cells of Rhv. sulfidophilum were grown under different conditions in the presence of 32P-phosphate and the corresponding H and L membrane fractions obtained and fractionated by SDS-PAGE. Both membranes showed almost identical polypeptide composition. The bacteriochlorophyll (Bchl) specific content in H was always lower that in L. As described befor...

The action of reducing, oxidizing and thiol-alkylating agents on early steps of Junin virus (JV) multiplication in Vero cells was investigated. The presence of reducing agents during virus adsorption as well as incubation of viral particles with these compounds before infection enhanced JV infectivity. On the contrary, the thiol-alkylating agent 5,...

The chemical nature of cellular structures involved in the attachment of Junin virus (wild type XJC13 and host range mutant Cl 67) to Vero cells was investigated. Enzyme treatment of cells before virus infection indicated that whereas lipids are not directly involved in virus attachment, cellular proteins play a significant role in early interactio...