Hyperoxia enhances brain-derived neurotrophic factor and tyrosine kinase B receptor expression in peribronchial smooth muscle of neonatal rats

Airway hyperreactivity is one of the hallmarks of hyperoxic lung injury in early life. As neurotrophins such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are potent mediators of neuronal plasticity, we hypothesized that neurotrophin levels in the pulmonary system may be disturbed by hyperoxic exposure. We therefore evaluated the effects of hyperoxia on the expression of BDNF, NGF, and their corresponding high-affinity receptors, TrkB and TrkA, respectively, in the lung of rat pups. Five-day-old Sprague-Dawley rat pups were randomized to hyperoxic or control groups and then continuously exposed to hyperoxia (>95% oxygen) or normoxia over 7 days. At both mRNA and protein levels, BDNF was detected in lung but not in trachea; its level was substantially enhanced in lungs from the hyperoxia-exposed rat pups. Distribution of BDNF mRNA by in situ hybridization indicates that peribronchial smooth muscle was the major source of increased BDNF production in response to hyperoxic exposure. Interestingly, hyperoxia-induced elevation of BDNF was not accompanied by any changes of NGF levels in lung. Furthermore, hyperoxic exposure increased the expression of TrkB in peribronchial smooth muscle but had no effect on the distribution of the specific NGF receptor TrkA. These findings indicate that hyperoxic stress not only upregulates BDNF at mRNA and protein levels but also enhances TrkB within peribronchial smooth muscle. However, there was no corresponding effect on NGF and TrkA receptors. We speculate that the increased level of BDNF may contribute to hyperoxia-induced airway hyperresponsiveness in early postnatal life.     

A bioactive annuionone from sunflower leaves

From aqueous extract of Helianthus annuus L. cv. Suncross-42 leaves, a annuionone have been isolated. The structural elucidation of the compound is based on 1H and 13C NMR spectral studies. The potential of the compound to be used as natural herbicide template has been evaluated through laboratory bioassays against five weed species. Results proved annuionone H as a potent plant growth inhibitor that can be exploit for the development of a herbicide model.     

Effect of protoplast source and media on growth and regenerability of protoplast-derived calluses of Solanum tuberosum L

Freshly isolated mesophyll and suspensions-cell protoplasts of S. tuberosum cvs. Desiree and Maris Piper were cultured in different media i.e. modified MS, V-KM and MS-KM. Protoplast plating efficiencies were higher in MS-KM medium. Resulting protoplast-derived calluses were transferred either onto the medium of Bokelmann and Roest (1983) or that of Lam (1977) for shoot regeneration. Calluses derived from mesophyll cell protoplasts differentiated about 2 weeks earlier than calluses derived from suspension-cell protoplasts. Shoot initiation was also about 2 weeks earlier from calluses subcultured onto the former medium as compared to the latter.     

Cobalt ions recruit inflammatory cells in vitro through human Toll-like receptor 4

Metal-on-metal (MoM) hip replacements, often manufactured from a cobalt-chrome alloy, are associated with adverse reactions including soft tissue necrosis and osteolysis. Histopathological analysis of MoM peri-implant tissues reveals an inflammatory cell infiltrate that includes macrophages, monocytes and neutrophils.Toll-like receptor 4 (TLR4) is an innate immune receptor activated by bacterial lipopolysaccharide. Recent studies have demonstrated that cobalt ions from metal-on-metal joints also activate human TLR4, increasing cellular secretion of inflammatory chemokines including interleukin-8 (IL-8, CXCL8) and CCL2. Chemokines recruit immune cells to the site of inflammation, and their overall effect depends on the chemokine profile produced.This study investigated the effect of cobalt on the secretion of inflammatory cytokines CCL20 and IL-6. The chemotactic potential of conditioned media from a cobalt-stimulated human monocyte cell line on primary monocytes and neutrophils was investigated using an in vitro transwell migration assay. The role of TLR4 in observed effects was studied using a small molecule TLR4-specific antagonist.Cobalt ions significantly increased release of CCL2 and IL-6 by MonoMac 6 cells (P<0.001). Conditioned media from cobalt-stimulated cells significantly increased monocyte and neutrophil chemotaxis in vitro (P<0.001). These effects were abrogated by the TLR4 antagonist (P<0.001) suggesting that they occur through cobalt activation of TLR4.This study demonstrates the role of TLR4 in cobalt-mediated immune cell chemotaxis and provides a potential mechanism by which cobalt ions may contribute to the immune cell infiltrate surrounding failed metal hip replacements. It also highlights the TLR4 signalling pathway as a potential therapeutic target in preventing cobalt-mediated inflammation.     

Arbuscular mycorrhizal symbiosis and abiotic stress in plants: A review

Abiotic stresses (such as salinity, drought, cold, heat, mineral deficiency and metals/metalloids) have become major threats to the global agricultural production. These stresses in isolation and/or combination control plant growth, development and productivity by causing physiological disorders, ion toxicity, and hormonal and nutritional imbalances. Some soil microorganisms like arbuscular mycorhizal fungi (AMF) inhabit the rhizosphere and develop a symbiotic relationship with the roots of most plant species. AMF can significantly improve resistance of host plants to varied biotic and abiotic stresses. Taking into account recent literature, this paper: (a) overviews major abiotic stresses and introduces the arbuscular mycorrhizae symbiosis (b) appraises the role and underlying major mechanisms of AMF in plant tolerance to major abiotic stresses including salinity, drought, temperature regimes (cold and heat), nutrient-deficiency, and metal/metalloids; (c) discusses major molecular mechanisms potentially involved in AMF-mediated plant-abiotic stress tolerance; and finally (d) highlights major aspects for future work in the current direction.     

Evolutionary and plastic changes in a native annual plant after a historic drought

Severe droughts are forecast to increase with global change. Approaches that enable the study of contemporary evolution, such as resurrection studies, are valuable for providing insights into the responses of populations to global change. In this study, we used a resurrection approach to study the evolution of the California native Leptosiphon bicolor (true babystars, Polemoniaceae) across populations differing in precipitation in response to the state's recent prolonged drought (2011–2017). In the Mediterranean climate region in which L. bicolor grows, this historic drought effectively shortened its growing season. We used seeds collected both before and after this drought from three populations found along a moisture availability gradient to assess contemporary evolution in a common garden greenhouse study. We coupled this with a drought experiment to examine plasticity. We found evolution toward earlier flowering after the historic drought in the wettest of the three populations, while plasticity to experimental drought was observed across all three. We also observed trade‐offs associated with earlier flowering. In the driest population, plants that flowered earlier had lower intrinsic water‐use efficiency than those flowering later, which was an expected pattern. Unexpectedly, earlier flowering plants had larger flowers. Two populations exhibited evolution and plasticity toward smaller flowers with drought. The third exhibited evolution toward larger flowers, but displayed no plasticity. Our results provide valuable insights into differences among native plant populations in response to drought.     

Maternal celiac disease autoantibodies bind directly to syncytiotrophoblast and inhibit placental tissue transglutaminase activity

Background  

Celiac disease (CD) occurs in as many as 1 in 80 pregnant women and is associated with poor pregnancy outcome, but it is not known if this is an effect on maternal nutrient absorption or, alternatively, if the placenta is an autoimmune target. The major autoantigen, tissue transglutaminase (tTG), has previously been shown to be present in the maternal-facing syncytiotrophoblast plasma membrane of the placenta.     

Tetracycline and Chloramphenicol Efficiency Against Selected Biofilm Forming Bacteria

Despite the constantly increasing need for new antimicrobial agents, antibiotic drug discovery and development seem to have greatly decelerated in recent years. Presented with the significant problem of advancing antimicrobial resistance, the global scientific community has attempted to find alternative solutions; one of the most promising ones is the evaluation and use of old antibiotic compounds. A number of old antibiotic compounds, such as aminoglycosides, chloramphenicol, and tetracycline, are re-emerging as valuable alternatives for the treatment of difficult-to-treat infections. This study examined the in vitro potency for biofilm formation of five isolates (Klebsiella sp., Pseudomonas aeruginosa, Achromobacter sp., Klebsiella pneumoniae, and Bacillus pumilis) and the effects of antibiotics on these biofilms. Furthermore the quantitative analysis of planktonic, loosely attached cells, and their susceptibility to antibiotics was also determined. Twitching motility was observed to determine any effect in the biofilm forming capability of the isolates. All the isolates tested were efficient biofilm-forming strains in the polypropylene and borosilicate test tubes. Standard bacterial enumeration technique and CV staining produced equivalent results both in biofilm and planktonic assays. The biofilm formation of all the strains was affected in the presence of tetracycline or chloramphenicol. Highly significant decrease (P < 0.01) in biofilm formation was observed by treatment with chloramphenicol compared to tetracycline. In addition, the two antibiotics also affected adversely the planktonic and loosely attached cells of all isolates. Thus, testing the effects of older antibiotics on biofilms may supply useful information in addition to standard in vitro testing, particularly in diseases where biofilm formation is involved in the pathogenesis.