Commercial development of microalgal biotechnology: from the test tube to the marketplace.

: Significant progress has been made with solution of location problems and in preprocessing and decomposition for discrete optimization. There has also been research on the application of techniques from combinational optimization to nonlinear problems.

http://www.dtic.mil/dtic/tr/fulltext/u2/a273552.pdf

Discrete Applied Mathematics

Transgenesis in algae is a complex and fast-growing technology. Selectable marker genes, promoters, reporter genes, transformation techniques, and other genetic tools and methods are already available for various species and currently ~25 species are accessible to genetic transformation. Fortunately, large-scale sequencing projects are also planned, in progress, or completed for several of these species; the most advanced genome projects are those for the red alga Cyanidioschyzon merolae, the diatom Thalassiosira pseudonana, and the three green algae Chlamydomonas reinhardtii, Volvox carteri and Ostreococcus tauri. The vast amount of genomic and EST data coming from these and a number of other algae has the potential to dramatically enlarge not only the algae’s molecular toolbox. A powerful driving force in algal transgenics is the prospect of using genetically modified algae as bioreactors. In general, today’s non-transgenic, commercial algal biotechnology produces food additives, cosmetics, animal feed additives, pigments, polysaccharides, fatty acids, and biomass. But recent progress in algal transgenics promises a much broader field of application: molecular farming, the production of proteins or metabolites that are valuable to medicine or industry, seems to be feasible with transgenic algal systems. Indeed, the ability of transgenic algae to produce recombinant antibodies, vaccines, insecticidal proteins, or bio-hydrogen has already been demonstrated. Genetic modifications that enhance physiological properties of algal strains and optimization of algal production systems should further improve the potential of this auspicious technology in the future.

/pdf/algal-transgenics-and-biotechnology-3ov15b0ogb.pdf

Algal transgenics and biotechnology

Combinatorial Mathematics: THE PRINCIPLE OF INCLUSION AND EXCLUSION

Bijections and the Riordan group

Fifty cyanobacterial strains from different habitats(symbioses, soil, fresh and marine waters) belongingto the genus Nostoc were cultured and tested forbioactivity. Thirty-seven strains were isolated in ourlaboratory, the remaining were supplied by officialculture collections. All the organisms were grownunder controlled laboratory conditions. The biomasseswere lyophilised and extracted with ethanol:water toobtain a hydrophilic extract and then withdichloromethane:isopropanol to obtain a lipophilicextract. Both crude extracts were tested forantifungal (against Penicillium expansum andRhizoctonia solani) and antibacterial activity(against Agrobacterium vitis, Escherichiacoli and Staphylococcus epidermidis), and fortoxicity against Artemia salina nauplii.Twenty-four strains showed activity against at leastone of the target organisms. Bioactivity was equallydistributed between lipophilic and hydrophilicextracts, and was mostly directed against fungi (15strains) and Artemia nauplii (12 strains);antibacterial activity was less frequent (8 strains).The presence of bioactivity was independent of thestrain origin.

Bioactivity in free-living and symbiotic cyanobacteria of the genus Nostoc

We consider the class of L-convex polyominoes, i.e. those polyominoes in which any two cells can be connected with an ''L'' shaped path in one of its four cyclic orientations. The paper proves bijectively that the number f"n of L-convex polyominoes with perimeter 2(n+2) satisfies the linear recurrence relation f"n"+"2=4f"n"+"1-2f"n, by first establishing a recurrence of the same form for the cardinality of the ''2-compositions'' of a natural number n, a simple generalization of the ordinary compositions of n. Then, such 2-compositions are studied and bijectively related to certain words of a regular language over four letters which is in turn bijectively related to L-convex polyominoes. In the last section we give a solution to the open problem of determining the generating function of the area of L-convex polyominoes.

Combinatorial aspects of L-convex polyominoes

Enumeration of L-convex polyominoes by rows and columns

Our main purpose is to characterize the class of L-convex polyominoes introduced in [3] by means of their horizontal and vertical projections The achieved results allow an answer to one of the most relevant questions in tomography ie the uniqueness of discrete sets, with respect to their horizontal and vertical projections In this paper, by giving a characterization of L-convex polyominoes, we investigate the connection between uniqueness property and unimodality of vectors of horizontal and vertical projections In the last section we consider the continuum environment; we extend the definition of L-convex set, and we obtain some results analogous to those for the discrete case

/pdf/a-tomographical-characterization-of-l-convex-polyominoes-40pa0pq4c8.pdf

A tomographical characterization of l-convex polyominoes

ECO is a method for the recursive generation, and thereby also the enumeration of classes of combinatorial objects It has already found successful application in recent literature both to the exhaustive generation and to the uniform random generation of various objects classified according to several parameters of interest, as well as to their enumeration In this paper we extend this approach to the generation and enumeration of some classes of convex polyominoes We begin with a review of the ECO method and of the closely related notion of a succession rule  From this background, we develop the following principal findings: i) ECO constructions for both column-convex and convex polyominoes; ii) translations of these constructions into succession rules; iii) the consequent deduction of the generating functions of column-convex and of convex polyominoes according to their semi-perimeter, first of all analytically by means of the so-called kernel method , and then in a more novel manner by drawing on some ideas of Fedou and Garcia; iv) algorithms for the exhaustive generation of column convex and of convex polyominoes which are based on the ECO constructions of these object and which are shown to run in constant amortized time

/pdf/on-the-generation-and-enumeration-of-some-classes-of-convex-3z2r5mrozm.pdf

Andrea Frosini

Papers

Bioactivity in free-living and symbiotic cyanobacteria of the genus Nostoc

Combinatorial aspects of L-convex polyominoes

Enumeration of L-convex polyominoes by rows and columns

A tomographical characterization of l-convex polyominoes

On the Generation and Enumeration of some Classes of Convex Polyominoes