Phylogenetic utility of ycf1 in orchids: a plastid gene more variable than matK

Plastid DNA sequences have been widely used by systematists for reconstructing plant phylogenies. The utility of any DNA region for phylogenetic analysis is determined by ease of amplification and sequencing, confidence of assessment in phylogenetic character alignment, and by variability across broad taxon sampling. Often, a compromise must be made between using relatively highly conserved coding regions or highly variable introns and intergenic spacers. Analyses of a combination of these types of DNA regions yield phylogenetic structure at various levels of a tree (i.e., along the spine and at the tips of the branches). Here, we demonstrate the phylogenetic utility of a heretofore unused portion of a plastid protein-coding gene, hypothetical chloroplast open reading frame 1 (ycf1), in orchids. All portions of ycf1 examined are highly variable, yet alignable across Orchidaceae, and are phylogenetically informative at the level of species. In Orchidaceae, ycf1 is more variable than matK both in total number of parsimony informative characters and in percent variability. The nrITS region is more variable than ycf1, but is more difficult to align. Although we only demonstrate the phylogenetic utility of ycf1 in orchids, it is likely to be similarly useful among other plant taxa.     

GAC1, a gene encoding a putative GTPase-activating protein, regulates bikaverin biosynthesis in Fusarium verticillioides

Fusarium verticillioides (teleomorph Gibberella moniliformis) is an ascomycete known to produce a variety of secondary metabolites, including fumonisins, fusaric acid and bikaverin. These metabolites are synthesized when the fungus is under stress, notably nutrient limitations. To date we have limited understanding of the complex regulatory process associated with fungal secondary metabolism. In this study we generated a collection of F. verticillioides mutants by using REMI (restriction enzyme mediated integration) mutagenesis and in the process identified a strain, R647, that carries a mutation in a gene designated GAC1. Mutation in the GACI locus, which encodes a putative GTPase activating protein, resulted in the increased production of bikaverin, suggesting that GAC1 is negatively associated with bikaverin biosynthesis. Complementation of R647 with the wildtype GAC1 gene restored the bikaverin production level to that of the wild-type progenitor, demonstrating that gac1 mutation was directly responsible for the overproduction of bikaverin. We also demonstrated that AREA, encoding global nitrogen regulator, and PKS4, encoding polyketide synthase, are downstream genes that respectively are regulated positively and negatively by GAC1. Our results suggest that GAC1 plays an important role in signal transduction regulating bikaverin production in F. verticillioides.     

Encapsulation of crosslinked penicillin G acylase aggregates in lentikats: evaluation of a novel biocatalyst in organic media

The encapsulation of crosslinked enzyme aggregates (CLEA) of penicillin G acylase into a very rigid polymeric matrix based on polyvinyl alcohol (LentiKats) has been used successfully to improve the inadequate mechanical properties of CLEA. This encapsulation decreased CLEA activity by only around 40%. As compensation, a significant improvement in the stability of the CLEA in the presence of organic solvents was detected. This could be related to the highly hydrophilic environment inside the LentiKats biocatalysts: Partition experiments showed that the concentration of dioxane inside LentiKats was lower than in the reaction medium. In fact, thermal stability was about the same as in the corresponding CLEA. This permitted great improvement in the reaction rate for thermodynamically controlled synthesis of a model antibiotic (using phenylacetic acid and 7-amino-deacetoxycefalosporanic acid). Even more importantly, yields could be improved by using LentiKats-encapsulated CLEA, very likely by a favorable product/substrate partition. Thus, this very simple technique not only provides an efficient technique for solving the mechanical stability problem associated with CLEA, but also greatly improves the behavior of CLEA in organic media.     

Distribution of microcystin-producing and non-microcystin-producing Microcystis sp. in European freshwater bodies: detection of microcystins and microcystin genes in individual colonies

Microcystis is a well-known cyanobacterial genus frequently producing hepatotoxins named microcystins. Toxin production is encoded by microcystin genes (mcy). This study aims (i) to relate the mcy occurrence in individual colonies to the presence of microcystin, (ii) to assess whether morphological characteristics (morphospecies) are related to the occurrence of mcy genes, and (iii) to test whether there are geographical variations in morphospecies specificity and abundance of mcy genes. Individual colonies of nine different European countries were analysed by (1) morphological characteristics, (2) PCR to amplify a gene region within mcyA and mcyB indicative for microcystin biosynthesis, (3) matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) to detect microcystins. Almost one hundred percent of the colonies predicted to produce microcystins by PCR analysis were found to contain microcystins. A high similarity in microcystin variants in the different colonies selected from lakes across Europe was demonstrated. The different morphospecies varied in the frequency with which they contained mcy genes. Most colonies (>75%) of M. aeruginosa and M. botrys contained the mcy genes, whereas < or = 20% of the colonies identified as M. ichthyoblabe and M. viridis gave a PCR product of the mcy genes. No colonies of M. wesenbergii gave a PCR product of either mcy gene. In addition, a positive relationship was found between the size of the colony and the frequency of those containing the mcy genes. It is concluded that the analysis of morphospecies is indicative for microcystin production, although the quantitative analysis of microcystin concentrations in water remains indispensable for hazard control.     

Reproductive traits of the small Patagonian octopus Octopus tehuelchus

This study evaluated the reproductive features of Octopus tehuelchus in three coastal environments of San Matías Gulf (Patagonia). Monthly samples of O. tehuelchus were used to estimate size at maturity, compare seasonal changes in oocyte size frequency distributions between sites as well as oocyte number and size between female maturity stage and sites. Females in Islote Lobos had a smaller size at maturity than females in San Antonio Bay and El Fuerte, probably as a consequence of a generally smaller body size. Males in San Antonio Bay were smaller at maturity than females. O. tehuelchus is a simultaneous terminal spawner. Fecundity (expressed as number of vitellogenic oocytes in ovary) was lower in Islote Lobos, and an increase in oocyte number in relation to female total weight was found. Females in San Antonio Bay had the largest oocytes, which may indicate higher energy reserves for the embryo and therefore higher juvenile survival. There was a close relationship between reproduction, growth and condition, represented as size at maturity, number and size of vitellogenic oocytes and period of maturity and spawning. Given the local variation in some reproductive features of O. tehuelchus, studies should focus on the environmental factors, which bring about this variation, and on how it affects the dynamics of local populations.