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68
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Introduction
Additional affiliations
August 2003 - present
Centro para el Estudio de Sistemas Marinos (CESIMAR), Centro Nacional Patagonico
Position
- Researcher
October 1998 - March 2003
University of Tennessee
April 1992 - September 1998
Education
April 1992 - March 2008
Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina
Field of study
- Microbiology
March 1987 - March 1992
Publications
Publications (68)
Kelp forests, among the most productive ecosystems on Earth, cover large areas of the South Atlantic coast. Sediment heterotrophic bacteria have a pivotal role in the degradation of kelp biomass, however, the response of sediment microbial communities to periodic kelp biomass inputs is mostly unknown. Here, we show that kelp biomass induced rapid c...
Small genes (<150 nucleotides) have been systematically overlooked in phage genomes. We employ a large-scale comparative genomics approach to predict >40,000 small-gene families in ∼2.3 million phage genome contigs. We find that small genes in phage genomes are approximately 3-fold more prevalent than in host prokaryotic genomes. Our approach enric...
Undaria pinnatifida is a brown algae native to Asia that has settled in various regions worldwide, periodically contributing with large quantities of C and nutrients during its annual cycle. In this work, we analyzed a coastal site in Patagonia (Argentina) that has been colonized for three decades by U. pinnatifida, focusing on associated microbial...
The invasive kelp Undaria pinnatifida has spread from northeastern Asia to temperate coastal environments worldwide, with profound effects on colonized ecosystems. In this work, we analyzed the effect of exudates from U. pinnatifida on the chemical and microbial properties of seawater from a semi-enclosed gulf from Atlantic Patagonia. Exudates of U...
A Correction to this paper has been published: https://doi.org/10.1038/s41587-021-00898-4.
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
The invasive kelp Undaria pinnatifida has spread from northeastern Asia to temperate coastal environments worldwide, with profound effects on colonized ecosystems. In this work, we analyzed the effect of exudates from U. pinnatifida on the chemical and microbial properties of seawater from a semi-enclosed gulf from Atlantic Patagonia. Exudates of U...
Despite recent advances in metagenomics, increasing our understanding of sediment microbial communities remains a challenge because of their remarkable diversity. In this chapter we describe various strategies for the analysis of metagenomes from complex microbial communities, using a sequence dataset of coastal sediments from Antarctic and sub-Ant...
Aromatic ring-hydroxylating oxygenases (RHOs) are multicomponent enzymes that catalyze the vicinal hydroxylation of aromatic rings to produce cis-dihydrodiols, a key step in the aerobic biodegradation of aromatic compounds. In this work, we describe the characterization of three RHOs of an uncultured gammaproteobacterium from chronically polluted S...
The aim of this work was to characterize the microbial nitrogen cycling potential in sediments from Ushuaia Bay, a subantarctic environment that has suffered a recent explosive demographic growth. Subtidal sediment samples were retrieved in triplicate from two urban points in the Bay, and analyzed through metagenomic shotgun sequencing. Sequences a...
Physicochemical characteristics of Ushuaia Bay sediment samples.
Results are expressed as mean and standard deviation of 10 measurements, with the exception of TOM and NH4+, which were measured in triplicate.
(PDF)
Evolutionary placement analysis of putative NirK sequences identified in the metagenomes of Ushuaia Bay sediments.
The tree was constructed by Maximum Likelihood in RAxML v.8.2.3. Reference sequences are indicated by GenBank accession numbers followed by title. Metagenomic sequences are indicated with blue and red colored branches, for sediment sam...
Evolutionary placement analysis of putative NosZ sequences identified in the metagenomes of Ushuaia Bay sediments.
The tree was constructed by Maximum Likelihood in RAxML v.8.2.3. Reference sequences are indicated by GenBank accession numbers followed by title. Metagenomic sequences are indicated with blue and red colored branches, for OR and MC, r...
Relative abundance of the sequences assigned to Hao and NapA in various metagenomes, discriminated by type of environment.
Metagenomic sequences were annotated in the IMG/M pipeline. Abundances of specific KEGG orthology (KO) identifiers were retrieved as “estimated gene copies” (assembled and unassembled fractions), normalized to the total sequenc...
Similarity percentage (SIMPER) analysis of sediment metagenomes based on abundance of amino acid sequences assigned to N-cycling biomarker genes, grouped by site.
Bold types indicate biomarkers whose cumulative contribution to the relative dissimilarity was ≥ 90%.
(PDF)
Relative abundance of sequences assigned to biomarker genes for N-cycling in sediments from Ushuaia Bay, discriminated by sampling site.
Numbers correspond to percent amino acid sequences, with respect to total sequences assigned to KOs. Differences in abundances between sites were evaluated by Welch two-sample test (α = 0.05). *p-value <0.05; **p-...
Abundance of sequences assigned to genes encoding N-cycling enzymes selected for this study.
“Estimated gene copies, assembled and unassembled metagenomes” were obtained from sequences assigned to KO identifiers at the IMG database (www.img.jgi-doe.gov).
(PDF)
In this work, we analyzed the community structure and metabolic potential of sediment microbial communities in high-latitude coastal environments subjected to low to moderate levels of chronic pollution. Subtidal sediments from four low-energy inlets located in polar and subpolar regions from both Hemispheres were analyzed using large-scale 16S rRN...
Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about mi...
The goal of this work was to identify sequences encoding monooxygenase biocatalysts with novel features by in silico mining an assembled metagenomic dataset of polar and subpolar marine sediments. The targeted enzyme sequences were Baeyer–Villiger and bacterial cytochrome P450 monooxygenases (CYP153). These enzymes have wide-ranging applications, f...
Rhodopsins are broadly distributed and are light sensitive molecules. In this work we analyzed 23 metagenomes corresponding to marine sediment samples from four regions which share cold climate conditions (Norway; Sweden; Argentina and Antarctica). In order to investigate the genes evolution of viral-rodopsins, an initial set of 6224 bacterial rhod...
Alginates are abundant polysaccharides in brown algae that constitute an important energy source for marine heterotrophic bacteria. Despite the key role of alginate degradation processes in the marine carbon cycle, little information is available on the bacterial populations involved in these processes. The aim of this work was to gain a better und...
We aimed to gain insight into the alkane degradation potential of microbial communities from chronically polluted sediments of a subantarctic coastal environment using a combination of metagenomic approaches. A total of 6178 sequences annotated as alkane-1-monooxygenases (EC 1.14.15.3) were retrieved from a shotgun metagenomic dataset that included...
A combination of RT-PCR assays and of Northern blots were used to evaluate the ability of naphthalene, phenanthrene and pyrene to induce nahAc from three Pseudomonas isolates obtained from oil-contaminated marine sediments. Naphthalene dioxygenase activity based on indigo oxidation correlated with nahAc expression in all strains, while variable pol...
Aims: To investigate the potential to degrade polycyclic aromatic hydrocarbons (PAHs) of yet-to-be cultured bacterial populations from chronically-polluted intertidal sediments.
Methods and Results: A gene variant encoding the alpha subunit of the catalytic component of an aromatic ring-hydroxylating oxygenase (RHO) was abundant in intertidal sedim...
During evolution, microorganisms have accumulated a remarkable physiological and functional heterogeneity as a result of their adaptation to various environmental selective pressures. Marine microorganisms have been evolving and diversifying during billions of years in contrast to those from terrestrial habitats, which possess a much shorter evolut...
In previous studies we have mapped uric acid deposits in specialized tissues of the invading apple snail Pomacea canaliculata. Uric acid stores function as reservoirs of combined nitrogen in insects. The first step for recycling uric acid nitrogen involves the action of uricase and here we explored the occurrence of
uricase-positive bacteria in the...
The aim of this study was to design a molecular biological tool suitable for use in marine ecosystems for environmental assessment and bioremediation, using the information provided by amplicon pyrosequencing of 16S rRNA genes. We selected from the literature 63 bacterial genera previously linked to hydrocarbon biodegradation, as representing a min...
Este libro está dirigido al público en general, con algo de conocimientos sobre las ciencias biológicas adquiridos en la escuela media. Estudiantes de este nivel educativo, estudiantes de carreras terciarias y universitarias e integrantes de las oficinas de gobiernos interesados en esta temática fueron nuestra inspiración para la selección de los t...
Although sediments are the natural hydrocarbon sink in the marine environment, the ecology of hydrocarbon-degrading bacteria in sediments is poorly understood, especially in cold regions. We studied the diversity of alkane-degrading bacterial populations and their response to oil exposure in sediments of a chronically polluted Subantarctic coastal...
The marine environments of Argentina have a remarkable extension, as well as high biological productivity and biodiversity of both macro- and microorganisms. Despite having a great potential for biotechnological applications, the microorganisms inhabiting these ecosystems remain mostly unexplored and unexploited. In this review, we study the resear...
Novel polycyclic aromatic hydrocarbon dioxygenase gene variants were present in abundances similar to or higher than those
of phnA1 from Cycloclasticus spp. at a chronically polluted subantarctic coastal marine environment in Patagonia. These novel gene variants were detected
over a 6-year time span and were also present in sediments from temperate...
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...
With the goal of identifying functional biomarker genes associated with polycyclic aromatic hydrocarbon (PAH) biodegradation in chronically polluted Subantarctic marine sediments, we amplified from environmental metagenomic DNA, cloned and sequenced gene fragments encoding dioxygenase enzymes associated with the biodegradation of these compounds. I...
The goal of this study was to identify functional targets to detect polycyclic aromatic hydrocarbon (PAH)-degrading bacterial populations in cold marine ecosystems.
We designed a degenerate primer set targeting genes encoding the alpha subunit of PAH-dioxygenases from Gram-positive bacteria. This primer set was used to amplify gene fragments from m...
Biosurfactant-producing bacteria belonging to the genera Alcanivorax, Cobetia and Halomonas were isolated from marine sediments with a history of hydrocarbon exposure (Aristizábal and Gravina Peninsulas, Argentina). Two Alcanivorax isolates were found to form naturally occurring consortia with strains closely related to Pseudomonas putida and Micro...
The International Census of Marine Microbes (ICoMM), together with the South American and Caribbean Steering Committees of the Census of Marine Life program (CoML), supported the initiative of launching a regional lCoMM node (LACar ICoMM). This network aims at promoting discussions among scientists currently involved in marine microbial studies car...
Supplementary information of sampling sites. Latitude, longitude and description of sampling sites.
Sequence alignment of ARHDs. Deduced amino acid sequence alignment of the ARHD gene fragments found in the libraries, and related sequences.
Polycyclic aromatic hydrocarbons (PAHs), widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In...
Microorganisms will be an integral part of biologically based waste processing systems used for water purification or nutrient recycling on long-term space missions planned by the National Aeronautics and Space Administration. In this study, the function and stability of microbial inocula of different diversities were evaluated after inoculation in...
Expression of the bacterial luciferase (lux) system in mammalian cells would culminate in a new generation of bioreporters for in vivo monitoring and diagnostics technology. Past efforts to express bacterial luciferase in mammalian cells have resulted in only modest gains due in part to low overall expression of the bacterial genes. To optimize exp...
Ammonia-oxidizing bacterial populations in an industrial wastewater treatment plant were investigated with amoA and 16S rRNA gene real-time PCR assays. Nitrosomonas nitrosa initially dominated, but over time RI-27-type ammonia oxidizers, also within the Nitrosomonas communis lineage, increased from below detection to codominance. This shift occurre...
We designed a real-time PCR assay able to recognize dioxygenase large-subunit gene sequences with more than 90% similarity
to the Ralstonia sp. strain U2 nagAc gene (nagAc-like gene sequences) in order to study the importance of organisms carrying these genes in the biodegradation of naphthalene.
Sequencing of PCR products indicated that this real-...
Current mammalian bioreporters using either firefly luciferase (luc) or
GFP constructs require lysis and/or exogenous excitation to evoke a
measurable response. Consequently, these cells cannot serve as
continuous, on-line monitoring devices for in vivo imaging. Bacterial
luciferase, lux, produces a photonic reaction that is cyclic, resulting
in au...
A plasmid-based 16S–23S rDNA intergenic spacer region (ISR) array was developed and optimized for analysis of microbial diversity within complex environmental samples. Plasmid probes with 16S–23S rDNA ISR inserts (800–1500 bp) from industrial wastewater treatment plant (WWTP) microorganisms were arrayed onto glass slides. Hybridization of fluoresce...
The aims of this study were to determine the power of discrimination of the real-time PCR assay for monitoring fluctuations in microbial populations within activated sludge and to identify sample processing points where methodological changes are needed to minimize the variability in target quantification. DNA was extracted using a commercially ava...
Real-time PCR assays using TaqMan or Molecular Beacon probes were developed and optimized for the quantification of total bacteria, the nitrite-oxidizing bacteria Nitrospira, and Nitrosomonas oligotropha-like ammonia oxidizing bacteria (AOB) in mixed liquor suspended solids (MLSS) from a municipal wastewater treatment plant (WWTP) using a single-sl...
Nitrification was assessed in two full-scale wastewater treatment plants (WWTPs) over time using molecular methods. Both WWTPs employed a complete-mix suspended growth, aerobic activated sludge process (with biomass recycle) for combined carbon and nitrogen treatment. However, one facility treated primarily municipal wastewater while the other only...
The effect of solids retention time (SRT) on ammonia- and nitrite-oxidizing bacteria was measured by Nitrosomonas oligotropha-like ammonia monooxygenase A and Nitrospira 16S rDNA competitive polymerase chain reaction assays in a complete-mix, bench-scale, activated-sludge system. During steady-state operation, nitrification was complete in the 20-...
Utilizing the principle of competitive PCR, we developed two assays to enumerate Nitrosomonas oligotropha-like ammonia-oxidizing bacteria and nitrite-oxidizing bacteria belonging to the genus Nitrospira. The specificities of two primer sets, which were designed for two target regions, the amoA gene and Nitrospira 16S ribosomal DNA (rDNA), were veri...
Incubation of bovine liver mitochondrial rhodanese in dilute, reducing solutions at temperatures ranging between 30 and 45 degreesC conduced to a rapid loss of enzymatic activity. This inactivation was substantially reduced in the presence of millimolar concentrations of alkali metal ions, divalent cations (including Mg2+, Ca2+, and Ba2+) were inef...
Using an Escherichia coli strain (RF101) in which the endogenous chromosomal groESL operon was removed, we overexpressed the GroEL and GroES chaperonins cloned from the photosynthetic bacterium Chromatium vinosum. The identities of these proteins were confirmed by immunological and N-terminal sequence analyses. The native molecular masses of GroEL...
The DnaK system is required for the productive folding of pea chloroplast ferredoxin-NADP+ reductase (FNR) expressed in Escherichia coli. The formation of a mature active enzyme was severely impaired in E. coli dnaK, dnaJ or grpE mutants expressing either the cytosolic precursor of the reductase (preFNR) or the mature apoenzyme, and these forms agg...
Projects
Projects (2)
The goal of this research line is to identify novel enzymes that depolymerize polysaccharides from macroalgae in microbial communities from coastal environments of Patagonia, and to evaluate their potential biotechnological applications. In order to achieve this goal, we are mining datasets generated by high-throughput sequencing of both metagenomic DNA and fosmid DNA from a metagenomic library constructed from subantarctic sediments.