No evidence for learned mating discrimination in male Drosophila pseudoobscura

Background  

Since females often pay a higher cost for heterospecific matings, mate discrimination and species recognition are driven primarily by female choice. In contrast, frequent indiscriminate matings are hypothesized to maximize male fitness. However, recent studies show that previously indiscriminate males (e.g., Drosophila melanogaster and Poecilia reticulata) can learn to avoid heterospecific courtship. This ability of males to discriminate against heterospecific courtship may be advantageous in populations where two species co-occur if courtship or mating is costly.     

Development of dormancy in different lily genotypes regenerated in vitro

Dormancy development in four Lilium genotypes,L. speciosum, Star Gazer, C. King and Snow Queenregenerated in vitro was compared. Major factorsinfluencing dormancy development were the same for different genotypes andespecially L. speciosum and Star Gazer, that are closelyrelated, reacted similarly. Temperature was the main factor in dormancyinduction and breaking. The range of temperatures that induced dormancy and thelevel of dormancy that developed differed per genotype. In Star Gazer, dormancydeveloped gradually but in Snow Queen, dormancy developed very fast. Thereactions to temperature, reflected the climate in the area of origin. Abscisicacid deepened the level of dormancy induced by temperature but had no effectunder non-inductive temperature conditions. When abscisic acid synthesis wasblocked, no dormancy developed. Dormancy in all genotypes was broken by coldincubation for severalweeks. The cold requirement of the genotypes differed in line with the naturalwinter conditions in their habitat. The effect of hormones on dormancy breakingwas also investigated. A gibberellin treatment of 24 h brokedormancy in L. speciosum, Star Gazer and Snow Queen.     

Abnormal actomyosin assembly in proliferating and differentiating myoblasts upon expression of a cytosolic DMPK isoform

DMPK, the product of the mutated gene in myotonic dystrophy type 1, belongs to the subfamily of Rho-associated serine-threonine protein kinases, whose members play a role in actin-based cell morphodynamics. Not much is known about the physiological role of differentially localized individual DMPK splice isoforms. We report here that prominent stellar-shaped stress fibers are formed during early and late steps of differentiation in DMPK-deficient myoblast-myotubes upon complementation with the short cytosolic DMPK E isoform. Expression of DMPK E led to an increased phosphorylation status of MLC2. We found no such effects with vectors that encode a mutant DMPK E which was rendered enzymatically inactive or any of the long C-terminally anchored DMPK isoforms. Presence of stellar structures appears associated with changes in cell shape and motility and a delay in myogenesis. Our data strongly suggest that cytosolic DMPK participates in remodeling of the actomyosin cytoskeleton in developing skeletal muscle cells.     

Phytoremediation of Metal Contaminated Soil Using Willow: Exploiting Plant-Associated Bacteria to Improve Biomass Production and Metal Uptake

Short rotation coppice (SRC) of willow and poplar is proposed for economic valorization and concurrently as remediation strategy for metal contaminated land in northeast-Belgium. However, metal phytoextraction appears insufficient to effectuate rapid reduction of soil metal contents. To increase both biomass production and metal accumulation of SRC, two strategies are proposed: (i) in situ selection of the best performing clones and (ii) bioaugmentation of these clones with beneficial plant-associated bacteria. Based on field data, two experimental willow clones, a Salix viminalis and a Salix alba x alba clone, were selected. Compared to the best performing commercial clones, considerable increases in stem metal extraction were achieved (up to 74% for Cd and 91% for Zn). From the selected clones, plant-associated bacteria were isolated and identified. All strains were subsequently screened for their plant growth-promoting and metal uptake enhancing traits. Five strains were selected for a greenhouse inoculation experiment with the selected clones planted in Cd-Zn-Pb contaminated soil. Extraction potential tended to increase after inoculation of S. viminalis plants with a Rahnella sp. strain due to a significantly increased twig biomass. However, although bacterial strains showing beneficial traits in vitro were used for inoculation, increments in extraction potential were not always observed.     

In search of income reference points for SLCA using a country level sustainability benchmark (part 1): fair inequality. A contribution to the Oiconomy project

Purpose

This paper is part 1 of our twin articles on income reference points for Social Life Cycle Assessment (SLCA). Preventative costs based LCA systems, such as the EcoCost system and the Oiconomy system, need targets (performance reference points) to determine the marginal preventative costs, the costs of the most expensive measure that globally needs to be employed to reach the target. To extend the EcoCost system for social issues, targets are required for issues like fair wages and fair inequality of wages, issues for which no agreed standard, no effect level or target exists. One way of setting targets is to take best practices as benchmark, e.g. the practices of a group of best performing countries. The purpose of this part 1 article is to first develop a well-founded benchmark group of the 20 % best performing countries and thereafter propose a well-founded target for the issue of inequality for preventative costs based SLCA, which can also serve as performance reference point for SLCA in general and for other uses. In part 2, for the same purposes and using the same benchmark group, we propose targets for fair minimum wages for every country.

Methods

A benchmark group of countries for the setting of targets was determined by an assessment of available country performance indicators, based on 5 criteria. Thereafter, we derived a proposal for a maximum inequality ratio based on existing democratically determined inequality ratios in the benchmark group.

Results and discussion

The Sustainable Society Index–Human Wellbeing proved the best indicator for a country benchmark for preventative cost-based SLCA. Using the average of maximum democratically determined income differences in a benchmark group of countries determined by this index, a performance reference point for SLCA for the issue of fair inequality was derived and proposed, resulting in a maximum ratio of income differences for governmental institutions of 14.1, for government ruled companies of 18.3 and for industry of a factor 23.8.

Conclusions

It proved possible to derive a target for maximum inequality of wages, based on democratic choices in a benchmark group of the 20 % best performing countries. The target for governmental institutions may be called objective, and proposed augmentations for government ruled companies and industry, though value choices, seem reasonable for the consumer who requires prevention of all possible harm as consequence of his purchase choices and who, as a voter, contributes to governmental standards.

     

Identification and mapping of loci involved in motility, adsorption to wheat roots, colony morphology, and growth in minimal medium on the Azospirillum brasilense Sp7 90-MDa plasmid.

We have constructed a cosmid library of the Azospirillum brasilense Sp7 90-MDa plasmid (p90) and established the EcoRI restriction map of this plasmid. The central regions of cloned p90 DNA fragments from several recombinant cosmids were deleted by restriction endonuclease digestion and replaced by a DNA cassette encoding kanamycin resistance. Using these in vitro constructed deletions for marker exchange in Sp7, we made six different p90 deletion derivatives spanning all together 50% of the total length of p90. Comparison of the deletion derivatives with Sp7 for several properties revealed p90 loci involved in colony morphology, growth on minimal medium, motility, and adsorption to wheat roots. In analogy with the rhizobial symbiotic plasmids (pSym), we propose to denote the p90 plasmid as a rhizocoenotic plasmid (pRhico), carrying several genes involved in the A. brasilense-plant root interaction.     

Induction of flower bud formation in vitro by dihydrozeatin

Flower stalk explants of tobacco cultured on a medium with an auxin and cytokinin regenerate flower buds within 14 days. The optimal medium concentrations of dihydrozeatin (DHZ) and benzyladenine (BA) were both 1 M. The presence of DHZ in the culture medium was only essential during an initiation period of 7 days, whereas BA was needed only during the first 4 days. The difference in length of the initiation period is neither explained by the unequal uptake rates of the cytokinins nor by differences in their conjugation. At the medium concentration optimal for bud formation, the internal concentration of DHZ was two to three times the internal concentration of BA, which could be attributed to faster uptake of DHZ. It is concluded from the combined data that DHZ is less active in inducing flower bud formation than BA and that the exogenous cytokinins play only a role during the initiation phase of bud regeneration.     

Thiophene interconversion in elicitor-treated roots ofTagetes patula L.

Thiophenes are polyacetylene-related heterocyclic metabolites. Some of these compounds are phototoxic, but the bithiophenes occurring inTagetes mainly accumulate in the root where photo-activation is not likely to occur. A cell-free extract from the fungusFusarium oxysporum induced biosynthesis of hydrophilic thiophenes in root cultures and roots of seedlings ofTagetes patula. The thiophenes formed were partially excreted into the culture medium. The excreted thiophenes inhibited fungal growth in the absence of light and thus may play a role in the biochemical defense against pathogens.Abbreviations BBT 5-(3-buten-1-ynyl)-2,2-bithienyl - BBTOAc 5-(4-acetoxy-1-butynyl)-2,2-bithienyl - BBT(OAc)₂ 5-(3,4-diacetoxy-1-butynyl)-2,2-bithienyl - BBTOH 5-(4-hydroxy-1-butynyl)-2,2-bithienyl - BBT(OH)₂ 5-(3,4-dihydroxy-1-butynyl)-2,2-bithienyl - HPLC high-performance liquid chromatography - UV ultraviolet