Values in evolutionary biology: a comparison between the contemporary debate on organic progress and Canguilhem's biological philosophy.

The aim of this paper is to make a comparison and build up a dialogue between two different philosophical approaches to values in evolutionary biology. First, I present the approach proposed by Alexander Rosenberg and Daniel McShea in their contribution to the contemporary debate on organic progress. i.e. the idea that there has been some kind of improvement concerning organisms over the history of life. Discussing organic progress raises the question of what "better" exactly means. This requires an explicit clarification on what legitimately means to speak about "good" in evolutionary biology, thus to speak about values. Second, I move on to present an approach to values that has been proposed by Georges Canguilhem in the context of a different philosophical tradition (i.e. the "continental" tradition). Canguilhem's original theses are conceived in a Darwinian framework and clearly relate to the question of values in evolutionary biology. I shall then propose a comparison between these two heterogeneous perspectives on values by critically evaluating their common points and main differences. I will argue that both perspectives agree that the question of values in evolutionary biology takes on its full meaning with respect to the relationship between the organism and the environment. However, the framework for conceptualizing values in evolutionary biology provided by Rosenberg and McShea neglects a significant point highlighted by Canguilhem, i.e. the active role that the organism can play in evaluating the environment. In line with recent developments of biology (e.g. niche construction), this point can be easily integrated into Rosenberg and McShea's framework. Finally, I will point out some main differences between the two perspectives relative to the specificity of Canguilhem's biological philosophy.

Direct monitoring of biocatalytic deacetylation of amino acid substrates by 1H NMR reveals fine details of substrate specificity.

Amino acids are key synthetic building blocks that can be prepared in an enantiopure form by biocatalytic methods. We show that the l-selective ornithine deacetylase ArgE catalyses hydrolysis of a wide-range of N-acyl-amino acid substrates. This activity was revealed by 1H NMR spectroscopy that monitored the appearance of the well resolved signal of the acetate product. Furthermore, the assay was used to probe the subtle structural selectivity of the biocatalyst using a substrate that could adopt different rotameric conformations.

The N-Acetyl Amino Acid Racemases (NAAARs); Native and evolved biocatalysts applied to the synthesis of canonical and non-canonical amino acids.

Amino acids are one of the most important synthons employed in the biotechnology, pharmaceutical and agrochemical industries for the preparation of active agents. Recently, the emerging use of these compounds as tools for protein engineering, has also been reported. Numerous chemo- and biocatalytic strategies have been developed for the stereoselective synthesis of these compounds. One of the most efficient processes is the enzymatic dynamic kinetic resolution of N-acylated derivatives, where an N-acyl amino acid racemase (NAAAR) is coupled with an enantioselective, hydrolytic enzyme (aminoacylase), and used to convert a racemic mixture of starting materials to enantiopure products. Here we provide a brief overview of the structure and mechanism of NAAAR. We will also review the applications of this class of biocatalyst, as well as discussing the various strategies employed to obtain an efficient system for the synthesis of optically pure canonical and non-canonical amino acids.

Disentangling organic and technological progress: An epistemological clarification introducing a key distinction between two levels of axiology.

The notion of "progress" can be defined as a directional change towards the better, implying both a descriptive and an axiological element. "Organic progress" refers to this notion applied to the history of life, whereas "technological progress" refers to this notion applied to the history of technological artifacts. This paper aims to disentangle conceptual questions about the notion of organic progress with respect to evolutionary theory, by proposing an epistemological perspective that also accounts for technological progress. My argument is set out in four sections. In section 2, drawing on the thought of some eminent evolutionary biologists, I will pinpoint a theoretical claim according to which a specific notion of organic progress is consistent with evolutionary theory. In section 3, I show some limits and problems that arise in the application of this theoretical claim to the organic domain. In section 4, I consider why these problems with application are often underestimated: I hypothesize that this is linked to the analogy frequently made between organic and technological progress. Finally, in section 5, I will carry on the analysis of this analogy by proposing a distinction between two levels of axiology. I claim that this distinction avoids several common confusions when talking about progress.

Bacterial Communities Associated with Four Cyanobacterial Genera Display Structural and Functional Differences: Evidence from an Experimental Approach.

To overcome the limitations associated with studying the interactions between bacterial communities (BCs) and cyanobacteria in natural environments, we compared the structural and functional diversities of the BCs associated with 15 non-axenic cyanobacterial strains in culture and two natural BCs sampled during cyanobacterial blooms. No significant differences in richness and diversity were found between the natural and cultivated BCs, although some of the cyanobacterial strains had been isolated 11 years earlier. Moreover, these BCs shared some similar characteristics, such as a very low abundance of Actinobacteria, but they display significant differences at the operational taxonomic unit (OTU) level. Overall, our findings suggest that BCs associated with cyanobacteria in culture are good models to better understand the interactions between heterotrophic bacteria and cyanobacteria. Additionally, BCs associated with heterocystous cyanobacterial strains cultivated in Z8X culture medium without nitrate (Aphanizomenon-Dolichospermum) demonstrated significant differences compared to BCs associated with non-heterocystous strains cultivated in Z8 culture medium (Planktothrix-Microcystis) in terms of their composition and their ability to utilize different carbon sources, suggesting the potential influence of cyanobacterial metabolism and/or culture media on associated BCs. Finally, half of the dominant OTUs in these BCs were specifically associated with cyanobacteria or other phytoplankton, whereas the remaining OTUs were generally associated with ecosystems containing high organic matter content, such as sludge or intestines.