The effect of turbidity on recognition and generalization of predators and non‐predators in aquatic ecosystems

Recent anthropogenic activities have caused a considerable change in the turbidity of freshwater and marine ecosystems. Concomitant with such perturbations are changes in community composition. Understanding the mechanisms through which species interactions are influenced by anthropogenic change has come to the forefront of many ecological disciplines. Here, we examine how a change in the availability of visual information influences the behavior of prey fish exposed to potential predators and non‐predators. When fathead minnows, Pimephales promelas, were conditioned to recognize predators and non‐predators in clear water, they showed a highly sophisticated ability to distinguish predators from non‐predators. However, when learning occurred under conditions of increased turbidity, the ability of the prey to learn and generalize recognition of predators and non‐predators was severely impaired. Our work highlights that changes at the community level associated with anthropogenic perturbations may be mediated through altered trophic interactions, and highlights the need to closely examine behavioral interactions to understand how species interactions change.     

Stomatal action directly feeds back on leaf turgor: new insights into the regulation of the plant water status from non‐invasive pressure probe measurements

Uptake of CO₂ by the leaf is associated with loss of water. Control of stomatal aperture by volume changes of guard cell pairs optimizes the efficiency of water use. Under water stress, the protein kinase OPEN STOMATA 1 (OST1) activates the guard‐cell anion release channel SLOW ANION CHANNEL‐ASSOCIATED 1 (SLAC1), and thereby triggers stomatal closure. Plants with mutated OST1 and SLAC1 are defective in guard‐cell turgor regulation. To study the effect of stomatal movement on leaf turgor using intact leaves of Arabidopsis, we used a new pressure probe to monitor transpiration and turgor pressure simultaneously and non‐invasively. This probe permits routine easy access to parameters related to water status and stomatal conductance under physiological conditions using the model plant Arabidopsis thaliana. Long‐term leaf turgor pressure recordings over several weeks showed a drop in turgor during the day and recovery at night. Thus pressure changes directly correlated with the degree of plant transpiration. Leaf turgor of wild‐type plants responded to CO₂, light, humidity, ozone and abscisic acid (ABA) in a guard cell‐specific manner. Pressure probe measurements of mutants lacking OST1 and SLAC1 function indicated impairment in stomatal responses to light and humidity. In contrast to wild‐type plants, leaves from well‐watered ost1 plants exposed to a dry atmosphere wilted after light‐induced stomatal opening. Experiments with open stomata mutants indicated that the hydraulic conductance of leaf stomata is higher than that of the root–shoot continuum. Thus leaf turgor appears to rely to a large extent on the anion channel activity of autonomously regulated stomatal guard cells.     

Assessing body composition with DXA and bioimpedance: effects of obesity, physical activity, and age

Objective: This study evaluated to what extent dual‐energy X‐ray absorptiometry (DXA) and two types of bioimpedance analysis (BIA) yield similar results for body fat mass (FM) in men and women with different levels of obesity and physical activity (PA). Methods and Procedures: The study population consisted of 37–81‐year‐old Finnish people (82 men and 86 women). FM% was estimated using DXA (GE Lunar Prodigy) and two BIA devices (InBody (720) and Tanita BC 418 MA). Subjects were divided into normal, overweight, and obese groups on the basis of clinical cutoff points of BMI, and into low PA (LPA) and high PA (HPA) groups. Agreement between the devices was calculated by using the Bland–Altman analysis. Results: Compared to DXA, both BIA devices provided on average 2–6% lower values for FM% in normal BMI men, in women in all BMI categories, and in both genders in both HPA and LPA groups. In obese men, the differences were smaller. The two BIA devices provided similar means for groups. Differences between the two BIA devices with increasing FM% were a result of the InBody (720) not including age in their algorithm for estimating body composition. Discussion: BIA methods provided systematically lower values for FM than DXA. However, the differences depend on gender and body weight status pointing out the importance of considering these when identifying people with excess FM.     

Preussia sp. BSL-10 producing nitric oxide,gibberellins, and indole acetic acid and improving rice plant growth

Preussia sp. have been least known to improve plant growth and produce phytohormones. The current study investigated the production of nitric oxide (NO), indole-3-acetic acid (IAA), and gibberellins (GA₄, GA₇, GA₁₅, and GA₅₃) by a novel endophytic-fungal strain Preussia sp. BSL-10 using advanced chromatographic and spectroscopic techniques. Production of these phytohormones were validated by RT–PCR analysis, which indicated the expression of genes encoding tryptophan synthase (TRP), indole-3-acetamide hydrolase (IAAH), tryptophan-2-monooxygenase (IAAM), aldehyde dehydrogenase (ALD), GA₄ desaturase (DES), geranylgeranyl-diphosphate synthase (GGS2), ent-desaturase oxidase (P450-4), GA₁₄ synthase (P450-1) and nitrite reductase (NIRK/NIRS), cytochrome P450 (P450nor), nitrate reductase (NR), NOS-like (NOL), and nitric oxide reductase (QNOR/CNOR). In plant growth-promoting effects, the inoculation of Preussia sp. BSL-10 significantly increased the growth of dwarf mutant Waito-C and wild-type rice cultivars. In conclusion, utilizing new endophytic with the ability to produce NO, IAA, and gibberellins can be used to promote growth and yield of marginalized crops.     

Morphology and Phylogeny of Three Trachelocercid Ciliates,with Description of a New Species,Trachelocerca orientalis spec. nov. (Ciliophora,Karyorelictea)

Three trachelocercid ciliates, Trachelocerca orientalis spec. nov., Prototrachelocerca fasciolata (Sauerbrey, 1928) Foissner, 1996 and Tracheloraphis huangi Xu et al., 2011, isolated from marine coastal habitats at Qingdao, China, were taxonomically studied using observation in vivo and silver staining methods. The new species T. orientalis spec. nov. can be recognized by the combination of its size (600–1,200 μm in vivo), 15–21 somatic kineties and about 13 groups of macronuclear nodules forming a strand and the colorless globular cortical granules. Together with the sequence data of the small subunit ribosomal RNA (SSU rRNA) gene, the information of a new isolate of P. fasciolata and three populations of T. huangi is also documented based on the present work. According to the molecular data, the phylogeny of three species is estimated and the analyses show that they are all found within the trachelocercid assemblage though T. huangi does not cluster with its congeners but with Trachelocerca species. Nonetheless, the monophyly of Trachelocerca is not rejected by the approximately unbiased test (p = 0.345 > 0.05), while that of Tracheloraphis is not confirmed (p = 0.0002 < 0.05).     

Drying Using Supercritical Fluid Technology as a Potential Method for Preparation of Chitosan Aerogel Microparticles

Supercritical fluid technology offers several advantages in preparation of microparticles. These include uniformity in particle size, morphology, and drug distribution without degradation of the product. One of the recent advantages is preparation of porous aerogel carrier with proper aerodynamic properties. In this study, we aimed to prepare chitosan aerogel microparticles using supercritical fluid (SCF) technology and compare that with microparticles produced by freeze drying (FD). Loading the prepared carriers with a model drug (salbutamol) was also performed. Comparisons of the particle properties and physicochemical characterizations were undertaken by evaluating particle size, density, specific surface area, and porosity. In vitro drug release studies were also investigated. The effect of many variables, such as molecular weight of chitosan oligomers, concentrations of chitosan, and concentrations of tripolyphosphate on the release, were also investigated. Chitosan aerogels were efficiently produced by SCF technology with an average particle size of 10 μm with a tapped density values around 0.12 g/mL, specific surface area (73–103) m²/g, and porosity (0.20–0.29) cc/g. Whereas, microparticles produced by FD method were characterized as cryogels with larger particle size (64 microns) with clear cracking at the surface. Sustained release profile was achieved for all prepared microparticles of salbutamol produced by the aforementioned methods as compared with pure drug. The results also demonstrates that chitosan molecular weight, polymer concentration, and tripolyphosphate concentration affected the release profile of salbutamol from the prepared microparticles. In conclusion, SCF technology was able to produce chitosan aerogel microparticles loaded with salbutamol that could be suitable for pulmonary drug delivery system.KEY WORDS: aerodynamic, aerogels, chitosan, salbutamol, supercritical fluid technology     

Salinomycin induces apoptosis and senescence in breast cancer: Upregulation of p21, downregulation of survivin and histone H3 and H4 hyperacetylation

Background

In the present study, we investigated the effect of Salinomycin on the survival of three human breast cancer cell lines MCF-7, T47D and MDA-MB-231 grown in adherent culture conditions.

Methods

Cell viability was measured by CellTiter-Glo and Trypan blue exclusion assay. Apoptosis was determined by caspase 3/7 activation, PARP cleavage and Annexin V staining. Cell cycle distribution was assessed by propidium iodide flow cytometry. Senescence was confirmed by measuring the senescence-associated β-galactosidase activity. Changes in protein expression and histone hyperacetylation was determined by western blot and confirmed by immunofluorescence assay.

Results

Salinomycinwas able to inhibit the growth of the three cell lines in time- and concentration-dependent manners. We showed that depending on the concentrations used, Salinomycin elicits different effects on theMDA-MB-231 cells. High concentrations of Salinomycin induced a G2 arrest, downregulation of survivin and triggered apoptosis. Interestingly, treatment with low concentrations of Salinomycin induced a transient G1 arrest at earlier time point and G2 arrest at later point and senescence associatedwith enlarged cellmorphology, upregulation of p21 protein, increase in histone H3 and H4 hyperacetylation and expression of SA-β-Gal activity. Furthermore, we found that Salinomycin was able to potentiate the killing of the MCF-7 and MDA-MB-231 cells, by the chemotherapeutic agents, 4-Hydroxytamoxifen and frondoside A, respectively.

Conclusion

Our data are the first to link senescence and histone modifications to Salinomycin.

Significance

This study provides a new insight to better understand the mechanism of action of Salinomycin, at least in breast cancer cells.