Bioactive molecules from protists: Perspectives in biotechnology

For hundreds of years, mankind has benefited from the natural metabolic processes of microorganisms to obtain basic products such as fermented foods and alcoholic beverages. More recently, microorganisms have been exploited for the production of antibiotics, vitamins and enzymes to be used in medicine and chemical industries. Additionally, several modern drugs, including those for cancer therapy, are natural products or their derivatives. Protists are a still underexplored source of natural products potentially of interest for biotechnological and biomedical applications. This paper focuses on some examples of bioactive molecules from protists and associated bacteria and their possible use in biotechnology.     

White biotechnology for cellulose manufacturing—The HoLiR concept

A variety of approaches are available for generation of bacteria‐produced nanocellulose (BNC) in different forms. BNC production under static cultivation conditions usually results in fleeces or foils, characterized by a homogeneous, three‐dimensional network of nanofibers and a uniform surface. However, under static cultivation conditions in batch vessels, the widths and the lengths of the BNC sheets cultured are determined by the dimensions of the culture vessel. In this contribution, a novel, efficient process for a (semi‐)continuous cultivation of planar BNC fleeces and foils with a freely selectable length and an adjustable height is presented. By means of comprehensive investigations, the comparability of the BNC harvested to that gained from static cultivation under batch conditions is demonstrated. A first estimation of the production costs further shows that this type of processing allows for significant cost reductions compared to static cultivation of BNC in Erlenmeyer flasks. Biotechnol. Bioeng. 2010. 105: 740–747. © 2009 Wiley Periodicals, Inc.     

Meeting report for the 4th Annual Complex Trait Consortium Meeting: From QTLs to Systems Genetics

The fourth annual meeting of the Complex Trait Consortium (CTC) was held in Groningen, the Netherlands on June 26–29, 2005. This meeting, which set a new attendance record, followed three previous and highly successful meetings. The focus at this meeting was on continued resource development and the exiting new field of systems genetics, the integration and anchoring of multi-dimensional data-types to underlying genetic variation. A new aspect at the meeting was the three-minute, ‘come see my poster’ presentations that generated significant interaction at the poster sessions. If the 2005 meeting is an indicator of things to come, future meetings promise to offer even more exciting research efforts to integrate high-throughput biological measurements with genetic variation to unravel the mechanisms responsible for inter-individual variation.     

Meeting report: Symbiosis in Barcelona

The European Congress on Biotechnology brought together the top European and International scientists, biotechnologists, innovators and key biotech policy and decision makers in an unprecedented international meeting. The Congress was established in 1978 by and remains the main activity of the European Federation of Biotechnology (EFB). Taking place in Barcelona, September 16–19, 2007, the ECB 13 attracted over 1500 leading scientists and other senior participants, over 500 posters and more than a hundred exhibitors, from over 50 countries across Europe and beyond. From over a 150 presentations in 5 and more parallel sessions, only a small fraction can be highlighted in the scope of this short meeting report.     

Meeting report: high-throughput technologies for in vivo imaging agents

Combinatorial chemistry and high-throughput screening have become standard tools for discovering new drug candidates with suitable pharmacological properties. Now, those same technologies are starting to be applied to the problem of discovering novel in vivo imaging agents. Important differences in the biological and pharmacological properties needed for imaging agents, compared to those for a therapeutic agent, require new screening methods that emphasize those characteristics, such as optimized residence time and tissue specificity, that make for a good imaging agent candidate.     

Gene and genon concept: coding versus regulation

We analyse here the definition of the gene in order to distinguish, on the basis of modern insight in molecular biology, what the gene is coding for, namely a specific polypeptide, and how its expression is realized and controlled. Before the coding role of the DNA was discovered, a gene was identified with a specific phenotypic trait, from Mendel through Morgan up to Benzer. Subsequently, however, molecular biologists ventured to define a gene at the level of the DNA sequence in terms of coding. As is becoming ever more evident, the relations between information stored at DNA level and functional products are very intricate, and the regulatory aspects are as important and essential as the information coding for products. This approach led, thus, to a conceptual hybrid that confused coding, regulation and functional aspects. In this essay, we develop a definition of the gene that once again starts from the functional aspect. A cellular function can be represented by a polypeptide or an RNA. In the case of the polypeptide, its biochemical identity is determined by the mRNA prior to translation, and that is where we locate the gene. The steps from specific, but possibly separated sequence fragments at DNA level to that final mRNA then can be analysed in terms of regulation. For that purpose, we coin the new term “genon”. In that manner, we can clearly separate product and regulative information while keeping the fundamental relation between coding and function without the need to introduce a conceptual hybrid. In mRNA, the program regulating the expression of a gene is superimposed onto and added to the coding sequence in cis - we call it the genon. The complementary external control of a given mRNA by trans-acting factors is incorporated in its transgenon. A consequence of this definition is that, in eukaryotes, the gene is, in most cases, not yet present at DNA level. Rather, it is assembled by RNA processing, including differential splicing, from various pieces, as steered by the genon. It emerges finally as an uninterrupted nucleic acid sequence at mRNA level just prior to translation, in faithful correspondence with the amino acid sequence to be produced as a polypeptide. After translation, the genon has fulfilled its role and expires. The distinction between the protein coding information as materialised in the final polypeptide and the processing information represented by the genon allows us to set up a new information theoretic scheme. The standard sequence information determined by the genetic code expresses the relation between coding sequence and product. Backward analysis asks from which coding region in the DNA a given polypeptide originates. The (more interesting) forward analysis asks in how many polypeptides of how many different types a given DNA segment is expressed. This concerns the control of the expression process for which we have introduced the genon concept. Thus, the information theoretic analysis can capture the complementary aspects of coding and regulation, of gene and genon.     

Ergot: from witchcraft to biotechnology

The ergot diseases of grasses, caused by members of the genus Claviceps , have had a severe impact on human history and agriculture, causing devastating epidemics. However, ergot alkaloids, the toxic components of Claviceps sclerotia, have been used intensively (and misused) as pharmaceutical drugs, and efficient biotechnological processes have been developed for their in vitro production. Molecular genetics has provided detailed insight into the genetic basis of ergot alkaloid biosynthesis and opened up perspectives for the design of new alkaloids and the improvement of production strains; it has also revealed the refined infection strategy of this biotrophic pathogen, opening up the way for better control. Nevertheless, Claviceps remains an important pathogen worldwide, and a source for potential new drugs for central nervous system diseases.