Pull or Push? Octopuses Solve a Puzzle Problem

Octopuses have large brains and exhibit complex behaviors, but relatively little is known about their cognitive abilities. Here we present data from a five-level learning and problem-solving experiment. Seven octopuses (Octopus vulgaris) were first trained to open an L shaped container to retrieve food (level 0). After learning the initial task all animals followed the same experimental protocol, first they had to retrieve this L shaped container, presented at the same orientation, through a tight fitting hole in a clear Perspex partition (level 1). This required the octopuses to perform both pull and release or push actions. After reaching criterion the animals advanced to the next stage of the test, which would be a different consistent orientation of the object (level 2) at the start of the trial, an opaque barrier (level 3) or a random orientation of the object (level 4). All octopuses were successful in reaching criterion in all levels of the task. At the onset of each new level the performance of the animals dropped, shown as an increase in working times. However, they adapted quickly so that overall working times were not significantly different between levels. Our findings indicate that octopuses show behavioral flexibility by quickly adapting to a change in a task. This can be compared to tests in other species where subjects had to conduct actions comprised of a set of motor actions that cannot be understood by a simple learning rule alone.     

Estimating and Analyzing Savannah Phenology with a Lagged Time Series Model

Savannah regions are predicted to undergo changes in precipitation patterns according to current climate change projections. This change will affect leaf phenology, which controls net primary productivity. It is of importance to study this since savannahs play an important role in the global carbon cycle due to their areal coverage and can have an effect on the food security in regions that depend on subsistence farming. In this study we investigate how soil moisture, mean annual precipitation, and day length control savannah phenology by developing a lagged time series model. The model uses climate data for 15 flux tower sites across four continents, and normalized difference vegetation index from satellite to optimize a statistical phenological model. We show that all three variables can be used to estimate savannah phenology on a global scale. However, it was not possible to create a simplified savannah model that works equally well for all sites on the global scale without inclusion of more site specific parameters. The simplified model showed no bias towards tree cover or between continents and resulted in a cross-validated r² of 0.6 and root mean squared error of 0.1. We therefore expect similar average results when applying the model to other savannah areas and further expect that it could be used to estimate the productivity of savannah regions.     

Inducible gene modification in the gastric epithelium of Tff1‐CreERT2, Tff2‐rtTA,Tff3‐luc mice

Temporal and spatial regulation of genes mediated by tissue‐specific promoters and conditional gene expression systems provide a powerful tool to study gene function in health, disease, and during development. Although transgenic mice expressing the Cre recombinase in the gastric epithelium have been reported, there is a lack of models that allow inducible and reversible gene modification in the stomach. Here, we exploited the gastrointestinal epithelium‐specific expression pattern of the three trefoil factor (Tff) genes and bacterial artificial chromosome transgenesis to generate a novel mouse strain that expresses the CreERT2 recombinase and the reverse tetracycline transactivator (rtTA). The Tg(Tff1‐CreERT2;Tff2‐rtTA;Tff3‐Luc) strain confers tamoxifen‐inducible irreversible somatic recombination and allows simultaneous doxycycline‐dependent reversible gene activation in the gastric epithelium of developing and adult mice. This strain also confers luciferase activity to the intestinal epithelium to enable in vivo bioluminescence imaging. Using fluorescent reporters as conditional alleles, we show Tff1‐CreERT2 and Tff2‐rtTA transgene activity in a partially overlapping subset of long‐term regenerating gastric stem/progenitor cells. Therefore, the Tg(Tff1‐CreERT2;Tff2‐rtTA;Tff3‐Luc) strain can confer intermittent transgene expression to gastric epithelial cells that have undergone previous gene modification, and may be suitable to genetically model therapeutic intervention during development, tumorigenesis, and other genetically tractable diseases. Birth Defects Research (Part A) 106:626–635, 2016. © 2016 Wiley Periodicals, Inc.     

Aminothiazoles inhibit osteoclastogenesis and PGE2 production in LPS‐stimulated co‐cultures of periodontal ligament and RAW 264.7 cells,and RANKL‐mediated osteoclastogenesis and bone resorption in PBMCs

Inflammatory mediator prostaglandin E₂ (PGE₂) contributes to bone resorption in several inflammatory conditions including periodontitis. The terminal enzyme, microsomal prostaglandin E synthase‐1 (mPGES‐1) regulating PGE₂ synthesis is a promising therapeutic target to reduce inflammatory bone loss. The aim of this study was to investigate effects of mPGES‐1 inhibitors, aminothiazoles TH‐848 and TH‐644, on PGE₂ production and osteoclastogenesis in co‐cultures of periodontal ligament (PDL) and osteoclast progenitor cells RAW 264.7, stimulated by lipopolysaccharide (LPS), and bone resorption in RANKL‐mediated peripheral blood mononuclear cells (PBMCs). PDL and RAW 264.7 cells were cultured separately or co‐cultured and treated with LPS alone or in combination with aminothiazoles. Multinucleated cells stained positively for tartrate‐resistant acid phosphatase (TRAP) were scored as osteoclast‐like cells. Levels of PGE₂, osteoprotegerin (OPG) and interleukin‐6, as well as mRNA expression of mPGES‐1, OPG and RANKL were analysed in PDL cells. PBMCs were treated with RANKL alone or in combination with aminothiazoles. TRAP‐positive multinucleated cells were analysed and bone resorption was measured by the CTX‐I assay. Aminothiazoles reduced LPS‐stimulated osteoclast‐like cell formation both in co‐cultures and in RAW 264.7 cells. Additionally, aminothiazoles inhibited PGE₂ production in LPS‐stimulated cultures, but did not affect LPS‐induced mPGES‐1, OPG or RANKL mRNA expression in PDL cells. In PBMCs, inhibitors decreased both osteoclast differentiation and bone resorption. In conclusion, aminothiazoles reduced the formation of osteoclast‐like cells and decreased the production of PGE₂ in co‐cultures as well as single‐cell cultures. Furthermore, these compounds inhibited RANKL‐induced bone resorption and differentiation of PBMCs, suggesting these inhibitors for future treatment of inflammatory bone loss such as periodontitis.     

Salt‐enhanced cultivation as a morphology engineering tool for filamentous actinomycetes: Increased production of labyrinthopeptin A1 in Actinomadura namibiensis

Salt‐enhanced cultivation as a morphology engineering tool for the filamentous actinomycete Actinomadura namibiensis was evaluated in 500‐mL shaking flasks (working volume 100 mL) with the aim of increasing the concentration of the pharmaceutically interesting peptide labyrinthopeptin A1. Among the inorganic salts added to a complex production medium, the addition of (NH₄)₂SO₄ led to the highest amount of labyrinthopeptin A1 production. By using 50 mM (NH₄)₂SO₄, the labyrinthopeptin A1 concentration increased up to sevenfold compared to the non‐supplemented control, resulting in 325 mg L^?1 labyrinthopeptin A1 after 10 days of cultivation. The performance of other ammonium‐ and sulfate‐containing salts (e.g., NH₄Cl, K₂SO₄) was much lower than the performance of (NH₄)₂SO₄. A positive correlation between the uptake of glycerol as one of the main carbon sources and nongrowth‐associated labyrinthopeptin productivity was found. The change in the cell morphology of A. namibiensis in conjunction with increased osmolality by the addition of 50 mM (NH₄)₂SO₄, was quantified by image analysis. A. namibiensis always developed a heterogeneous morphology with pellets and loose mycelia present simultaneously. In contrast to the non‐supplemented control, the morphology of (NH₄)₂SO₄‐supplemented cultures was characterized by smaller and circular pellets that were more stable against disintegration in the stationary production phase.     

Monitoring of biofilms grown on differentially structured metallic surfaces using confocal laser scanning microscopy

Imaging of biofilms on opaque surfaces is a challenge presented to researchers especially considering pathogenic bacteria, as those typically grow on living tissue, such as mucosa and bone. However, they can also grow on surfaces used in industrial applications such as food production, acting as a hindrance to the process. Thus, it is important to understand bacteria better in the environment they actually have relevance in. Stainless steel and titanium substrata were line structured and dotted surface topographies for titanium substrata were prepared to analyze their effects on biofilm formation of a constitutively green fluorescent protein (GFP)‐expressing Escherichia coli strain. The strain was batch cultivated in a custom built flow cell initially for 18 h, followed by continuous cultivation for 6 h. Confocal laser scanning microscopy (CLSM) was used to determine the biofilm topography. Biofilm growth of E. coli GFPmut2 was not affected by the type of metal substrate used; rather, attachment and growth were influenced by variable shapes of the microstructured titanium surfaces. In this work, biofilm cultivation in flow cells was coupled with the most widely used biofilm analytical technique (CLSM) to study the time course of growth of a GFP‐expressing biofilm on metallic surfaces without intermittent sampling or disturbing the natural development of the biofilm.