Rhamnose biosynthesis is not impaired by the deletion of putative genes, and , in sp. PCC 6803.

Cyanobacterial extracellular polymeric substances (EPS) mainly composed of heteropolysaccharides can be attached to the cell wall as capsular polysaccharides (CPS) or released to the environment as released polysaccharides (RPS). These polymers have an unusually high diversified monosaccharidic composition, making them attractive for biotechnological/biomedical applications. However, their production is still poorly understood, hindering their optimization for industrial needs.

Towards the rate limit of heterologous biotechnological reactions in recombinant cyanobacteria.

Background: Cyanobacteria have emerged as highly efficient organisms for the production of chemicals and biofuels. Yet, the productivity of the cell has been low for commercial application. Cyanobacterial photobiotransformations utilize photosynthetic electrons to form reducing equivalents, such as NADPH-to-fuel biocatalytic reactions.

Heterologous Production of Glycine Betaine Using sp. PCC 6803-Based Chassis Lacking Native Compatible Solutes.

Among compatible solutes, glycine betaine has various applications in the fields of nutrition, pharmaceuticals, and cosmetics. Currently, this compound can be extracted from sugar beet plants or obtained by chemical synthesis, resulting in low yields or high carbon footprint, respectively. Hence, in this work we aimed at exploring the production of glycine betaine using the unicellular cyanobacterium sp.

CRISPRi as a Tool to Repress Multiple Copies of Extracellular Polymeric Substances (EPS)-Related Genes in the Cyanobacterium sp. PCC 6803.

The use of the versatile cyanobacterial extracellular polymeric substances (EPS) for biotechnological/biomedical applications implies an extensive knowledge of their biosynthetic pathways to improve/control polymer production yields and characteristics. The multiple copies of EPS-related genes, scattered throughout cyanobacterial genomes, adds another layer of complexity, making these studies challenging and time-consuming. Usually, this issue would be tackled by generating deletion mutants, a process that in cyanobacteria is also hindered by the polyploidy.

Expression and activity of heterologous hydroxyisocaproate dehydrogenases in sp. PCC 6803 Δ.

Exploiting light to drive redox reactions is currently a hot topic since light is considered as an environmentally friendly source of energy. Consequently, cyanobacteria, which can use light e.g.

Design and Validation of Tools for Microbial Synthetic Biology Applications.

Synthetic Biology (SynBio) is a multidisciplinary field that brings together science, technology and engineering to expedite the design, creation and modification of genetic materials to be applied in living organisms or in vitro systems [...

Comparison of alternative integration sites in the chromosome and the native plasmids of the cyanobacterium Synechocystis sp. PCC 6803 in respect to expression efficiency and copy number.

Background: Synechocystis sp. PCC 6803 provides a well-established reference point to cyanobacterial metabolic engineering as part of basic photosynthesis research, as well as in the development of next-generation biotechnological production systems. This study focused on expanding the current knowledge on genomic integration of expression constructs in Synechocystis, targeting a range of novel sites in the chromosome and in the native plasmids, together with established loci used in literature.

Expanding the toolbox for sp. PCC 6803: validation of replicative vectors and characterization of a novel set of promoters.

Cyanobacteria are promising 'low-cost' cell factories since they have minimal nutritional requirements, high metabolic plasticity and can use sunlight and CO as energy and carbon sources. The unicellular sp. PCC 6803, already considered the 'green' , is the best studied cyanobacterium but to be used as an efficient and robust photoautotrophic chassis it requires a customized and well-characterized toolbox.

Modulation of Intracellular O Concentration in Escherichia coli Strains Using Oxygen Consuming Devices.

The use of cell factories for the production of bulk and value-added compounds is nowadays an advantageous alternative to the traditional petrochemical methods. Nevertheless, the efficiency and productivity of several of these processes can improve with the implementation of micro-oxic or anoxic conditions. In the industrial setting, laccases are appealing catalysts that can oxidize a wide range of substrates and reduce O to HO.

Identification of inner membrane translocase components of TolC-mediated secretion in the cyanobacterium Synechocystis sp. PCC 6803.

Cyanobacteria were the first organisms ever to perform oxygenic photosynthesis and still significantly contribute to primary production on a global scale. To assure the proper functioning of their primary metabolism and cell homeostasis, cyanobacteria must rely on efficient transport systems to cross their multilayered cell envelope. However, cyanobacterial secretion mechanisms remain largely unknown.

Improving a Synechocystis-based photoautotrophic chassis through systematic genome mapping and validation of neutral sites.

The use of microorganisms as cell factories frequently requires extensive molecular manipulation. Therefore, the identification of genomic neutral sites for the stable integration of ectopic DNA is required to ensure a successful outcome. Here we describe the genome mapping and validation of five neutral sites in the chromosome of Synechocystis sp.

HesF, an exoprotein required for filament adhesion and aggregation in Anabaena sp. PCC 7120.

Here, we report on the identification and characterization of a protein (Alr0267) named HesF, found in the extracellular milieu of Anabaena sp. PCC 7120 grown diazotrophically. hesF was found to be highly upregulated upon transition from non-nitrogen-fixing to nitrogen-fixing conditions, and the highest transcript levels were detected towards the end of the heterocyst differentiation process.

Selection of suitable reference genes for RT-qPCR analyses in cyanobacteria.

Cyanobacteria are a group of photosynthetic prokaryotes that have a diverse morphology, minimal nutritional requirements and metabolic plasticity that has made them attractive organisms to use in biotechnological applications. The use of these organisms as cell factories requires the knowledge of their physiology and metabolism at a systems level. For the quantification of gene transcripts real-time quantitative polymerase chain reaction (RT-qPCR) is the standard technique.

Infection levels and diversity of anisakid nematodes in blackspot seabream, Pagellus bogaraveo, from Portuguese waters.

The blackspot seabream, Pagellus bogaraveo, is a sparid fish of great economic importance in the northeast Atlantic. The main aim of this work was to assess the infection levels and diversity of anisakid nematodes parasitizing P. bogaraveo from Portuguese waters.

Construction of a chassis for hydrogen production: physiological and molecular characterization of a Synechocystis sp. PCC 6803 mutant lacking a functional bidirectional hydrogenase.

Cyanobacteria are photosynthetic prokaryotes that are promising 'low-cost' microbial cell factories due to their simple nutritional requirements and metabolic plasticity, and the availability of tools for their genetic manipulation. The unicellular non-nitrogen-fixing Synechocystis sp. PCC 6803 is the best studied cyanobacterial strain and its genome was the first to be sequenced.

Labrys portucalensis sp. nov., a fluorobenzene-degrading bacterium isolated from an industrially contaminated sediment in northern Portugal.

A detailed classification of a novel bacterial strain, designated F11(T), capable of degrading fluorobenzene as a sole carbon and energy source, was performed by using a polyphasic approach. This Gram-negative, rod-shaped, non-motile, non-spore-forming, aerobic bacterium was isolated from a sediment sample collected from an industrially contaminated site in northern Portugal. The predominant whole-cell fatty acids were C(19 : 0) cyclo omega8c, C(16 : 0), C(18 : 1)omega7c, C(18 : 0), C(18 : 0) 3-OH and C(16 : 0) 3-OH.

Role of respiration and glutathione in cadmium-induced oxidative stress in Escherichia coli K-12.

Cadmium is a widespread pollutant that has been associated with oxidative stress, but the mechanism behind this effect in prokaryotes is still unclear. In this work, we exposed two glutathione deficient mutants (DeltagshA and DeltagshB) and one respiration deficient mutant (DeltaubiE) to a sublethal concentration of cadmium. The glutathione mutants show a similar increase in reactive oxygen species as the wild type.

Methyloversatilis universalis gen. nov., sp. nov., a novel taxon within the Betaproteobacteria represented by three methylotrophic isolates.

The taxonomic positions and phylogenetic relationships of two new methylotrophic isolates from Lake Washington (USA) sediment, FAM5T and 500, and the previously described methylotrophic strain EHg5 isolated from contaminated soil in Estarreja (Portugal) were investigated. All three strains were facultative methylotrophs capable of growth on a variety of C1 and multicarbon compounds. Optimal growth occurred at pH 7.

Identification, mutagenesis, and transcriptional analysis of the methanesulfonate transport operon of Methylosulfonomonas methylovora.

Recently identified genes located downstream (3') of the msmEF (transport encoding) gene cluster, msmGH, and located 5' of the structural genes for methanesulfonate monooxygenase (MSAMO) are described from Methylosulfonomonas methylovora. Sequence analysis of the derived polypeptide sequences encoded by these genes revealed a high degree of identity to ABC-type transporters. MsmE showed similarity to a putative periplasmic substrate binding protein, MsmF resembled an integral membrane-associated protein, and MsmG was a putative ATP-binding enzyme.

Isolation and properties of methanesulfonate-degrading Afipia felis from Antarctica and comparison with other strains of A. felis.

Three novel strains of methylotrophic Afipia felis were isolated from several locations on Signy Island, Antarctica, and a fourth from estuary sediment from the River Douro, Portugal. They were identified as strains of the alpha-2 proteobacterium A. felis by 16S rRNA gene sequence analysis.

Novel pollutant-resistant methylotrophic bacteria for use in bioremediation.

Thirty one novel methylotrophic bacterial strains were isolated from a range of soil and sediment sources (both pristine and polluted) under different enrichment regimes. They were characterised physiologically and classified by their 16S rRNA gene sequence. A great taxonomical and phenotypical variety was recovered.

Strain PM2, a novel methylotrophic fluorescent Pseudomonas sp.

A novel bacterial strain, PM2, capable of growing on methanol, was isolated in alkaline conditions from a soil inoculum. This bacterium was characterized at the physiological, biochemical and molecular level. Based on biochemical and molecular data strain PM2 was classified as a novel member of the group of fluorescent pseudomonads.

Enrichment of microbial cultures able to degrade 1,3-dichloro-2-propanol: a comparison between batch and continuous methods.

Microbial cultures able to degrade xenobiotic compounds are the key element for biological treatment of waste effluents and are obtained from enrichment processes. In this study, two common enrichment methods, suspension batch and immobilized continuous, were compared. The main selection factor was the presence of 1,3-dichloro-2-propanol (1,3-DCP) as the single carbon source.