Role of terrestrial carbon in aquatic UV exposure and photoprotective pigmentation of meiofauna in subarctic lakes

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Glycerol-based sterilization bioindicator system from Bacillus atrophaeus: development, performance evaluation, and cost analysis

The development of new value-added applications for glycerol is of worldwide interest because of the environmental and economic problems that may be caused by an excess of glycerol generated from biodiesel production. A novel use of glycerol as a major substrate for production of a low-cost sterilization biological indicator system (BIS; spores on a carrier plus a recovery medium) was investigated. A sequential experimental design strategy was applied for product development and optimization. The proposed recovery medium enables germination and outgrowth of heat-damaged spores, promoting a D _160 °C value of 6.6?±?0.1 min. Bacillus atrophaeus spores production by solid-state fermentation reached a 2.3?±?1.2?×?10⁸?CFU/g dry matter. Sporulation kinetics results allowed this process to be restricted in 48 h. Germination kinetics demonstrated the visual identification of nonsterile BIS within 24 h. Performance evaluation of the proposed BIS against dry-heat and ethylene oxide sterilization showed compliance with the regulatory requirements. Cost breakdowns were from 41.8 (quality control) up to 72.8 % (feedstock). This is the first report on sterilization BIS production that uses glycerol as a sole carbon source, with significant cost reduction and the profitable use of a biodiesel byproduct.     

Carbonic anhydrase seven bundles filamentous actin and regulates dendritic spine morphology and density

Intracellular pH is a potent modulator of neuronal functions. By catalyzing (de)hydration of CO₂, intracellular carbonic anhydrase (CA_i) isoforms CA2 and CA7 contribute to neuronal pH buffering and dynamics. The presence of two highly active isoforms in neurons suggests that they may serve isozyme‐specific functions unrelated to CO₂‐(de)hydration. Here, we show that CA7, unlike CA2, binds to filamentous actin, and its overexpression induces formation of thick actin bundles and membrane protrusions in fibroblasts. In CA7‐overexpressing neurons, CA7 is enriched in dendritic spines, which leads to aberrant spine morphology. We identified amino acids unique to CA7 that are required for direct actin interactions, promoting actin filament bundling and spine targeting. Disruption of CA7 expression in neocortical neurons leads to higher spine density due to increased proportion of small spines. Thus, our work demonstrates highly distinct subcellular expression patterns of CA7 and CA2, and a novel, structural role of CA7.     

Identification of proteins that interact with catalytically active calcium-dependent protein kinases from <Emphasis Type="Italic">Arabidopsis</Emphasis>

Calcium-dependent protein kinases (CDPKs) are essential sensor-transducers of calcium signaling pathways in plants. Functional characterization of CDPKs is of great interest because they play important roles during growth, development, and in response to a wide range of environmental stimuli. The Arabidopsis genome encodes 34 CDPKs, but very few substrates of these enzymes have been identified. In this study, we exploited the unique characteristics of CDPKs to develop an efficient approach for the discovery of CDPK-interacting proteins. High-throughput, semi-automated yeast two-hybrid interaction screens with two different cDNA libraries each containing 18 million prey clones were performed using catalytically impaired and constitutively active AtCPK4 and AtCPK11 variants as baits. The use of the constitutively active versions of the CPK baits improved the recovery of positive interacting proteins relative to the wild type kinase. Titration of interaction strength by growth under increasing concentrations of 3-aminotriazole (3-AT), a histidine analog and competitive inhibitor of the His3 gene product, confirmed these results. Possible mechanisms for this observed improvement are discussed. The reproducibility of this approach was assessed by the overlap of several interacting proteins of AtCPK4 and AtCPK11 and the recovery of several putative substrates and indicated that yeast two-hybrid screens using constitutively active and/or catalytically impaired forms of CDPK provides a useful tool to identify potential substrates of the CDPK family and potentially the entire protein kinase superfamily. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Moose–vehicle collisions occur earlier in warm springs

After autumn, early summer is the most important moose–vehicle collision (MVC) season in Finland. We surveyed temporal distributions and long-term changes in the timing of MVCs using data of daily collisions that occurred throughout a 4-month season (April–July) for the period 1989–2011. By uniting the road districts, we first divided Finland into five study regions and calculated the annual dates by which 50 % of all the MVCs of the study season had taken place (median dates). Then, using all of the present nine road districts as areal units, we determined if the beginning of the growing season and the median dates of MVCs were correlated. A total of 13,233 MVCs occurred during the study period. In every region, considering the selected 4-month annual period, the number of MVCs was the lowest in April but started to increase in May and was highest in June or July. The timing of the median dates for MVCs in all regions shifted to an earlier date and was positively correlated with the beginning of the growing season in every road district. We believe that the beginning of the growing season correlates with the timing of moose spring migration from wintering areas to summer pastures and further, with the timing of MVCs. Regardless of the ultimate reason behind our findings, we emphasize the practical importance of our results, namely how the onset of spring can help predict timing of spring MVCs. We recommend that warning campaigns informing road users coincide with the annually changing MVC season.     

Molecular evidence for a diverse green algal community growing in the hair of sloths and a specific association with <Emphasis Type="Italic">Trichophilus welckeri</Emphasis>(Chlorophyta,Ulvophyceae)

Background  

Sloths are slow-moving arboreal mammals inhabiting tropical rainforests in Central and South America. The six living species of sloths are occasionally reported to display a greenish discoloration of their pelage. Trichophilus welckeri, a green algal species first described more than a century ago, is widely believed to discolor the animals fur and provide the sloth with effective camouflage. However, this phenomenon has not been explored in any detail and there is little evidence to substantiate this widely held opinion.     

Costs of reproduction as related to the timing of phenological phases in the dioecious Shrub Pistacia lentiscus L

Females of woody dioecious species usually devote more resources to reproduction than males. This may lead to a decrease in female survival and growth. The costs of reproduction, however, can be lightened through a number of mechanisms, as for example avoiding the temporal coincidence of reproduction and vegetative growth. The aim of this study was to evaluate whether males and females of P. lentiscus differ in the timing of their vegetative growth, and to assess whether the sequencing of vegetative growth and reproduction reduces reproductive costs. We monitored phenology in males and females. We also compared male and female allocation of nutrients and biomass in the branch, and the developmental stability of the growing shoots. We did this both prior to and at the end of the fruiting period. Males and females showed similar vegetative and flowering phenologies. Males invested more biomass in flowering, but the sexes showed equal vegetative biomass and nutrient content prior to the fruiting period. In female branches, no trade-off was found between fruit load and current-year vegetative growth. In P. lentiscus, avoiding the overlap of flowering, vegetative growth and fruiting probably contributes to reduce the immediate costs of reproductive efforts, both in males and females.     

Replacement of species along altitude gradients: the role of branch architecture

Background and aims

Plant species typical of cold and warm habitats differ in a suite of morpho-physio-phenological traits, although their evolutionary routes have been poorly explored. Here, it is advocated that traits typical of different climate regimes can be largely driven by contrasting branch architectures. This is explored within Saxifraga. First, an investigation was carried out to determine whether series Ceratophyllae (lateral inflorescences) is segregated to lowlands compared with Pentadactylis (terminal inflorescences). Then, two altitudinal vicariants, S. trifurcata (lowland, with lateral inflorescences) and S. canaliculata (highland, with apical inflorescences), were selected. It was hypothesized that apical flowering of S. canaliculata constrains its growth period, bringing with it traits typical of short growth season plants, and conversely for S. trifurcata.

Methods

The hypothesis was tested by measuring plant compactness and organ pre-formation in seven populations of these species along an altitude gradient.

Key Results

Most variables differed among species. Morphological variables at all scales support that the architecture of S. canaliculata generates a more compact habit. A higher number of primordia and earlier inflorescence pre-formation in S. canaliculata indicate that it begins organogenesis earlier. Data on organogenesis suggest that the different timing of inflorescence initiation may be the origin of the contrasting architectures. Within species, shoot compactness increased, and the length of lateral primordia decreased, as altitude increased. All other metrics were similar among locations of the same species at contrasting altitudes.

Conclusions

The hypotheses linking elevational segregation of species, architecture and pheno-morphological traits were validated at broad (gen. Saxifraga) and local (altitudinal vicariants) scales. This supports the initial idea that shoot architecture may to a large extent condition high altitude adaptive syndrome.Key words: Saxifraga, meristem activity, altitude, architecture, phenology, organogenesis