Cross-reactivity of a monoclonal antiglucocorticoid receptor antibody BuGR1 with glucocorticoid and mineralocorticoid receptors of various species

The reactivity of a monoclonal antibody BuGR1, raised against glucocorticoid receptors of rat liver, with glucocorticoid and mineralocorticoid receptors of mammalian (rabbit) and amphibian (A6 cells) origin was examined. The glucocorticoid receptors of rabbit kidney and liver and of A6 cells were labeled with tritiated dexamethasone. The mineralocorticoid receptors were labeled with tritiated aldosterone in the presence or absence of RU26988, depending on whether aldosterone was bound to glucocorticoid receptors (A6 cells) or not (rabbit kidney), in addition to its binding to mineralocorticoid receptors. BuGR1 did not recognize mineralocorticoid receptors of A6 cells and rabbit kidney. BuGR1 cross-reacted with glucocorticoid receptors of rabbit liver and kidney but not of A6 cells, suggesting that the domain of glucocorticoid receptors recognized by BuRG1 could be present only in the mammalian species. The findings indicate that BuGR1 shows species differences as well as receptor class specificity.     

Modelling pollination services across agricultural landscapes

Background and Aims

Crop pollination by bees and other animals is an essential ecosystem service. Ensuring the maintenance of the service requires a full understanding of the contributions of landscape elements to pollinator populations and crop pollination. Here, the first quantitative model that predicts pollinator abundance on a landscape is described and tested.

Methods

Using information on pollinator nesting resources, floral resources and foraging distances, the model predicts the relative abundance of pollinators within nesting habitats. From these nesting areas, it then predicts relative abundances of pollinators on the farms requiring pollination services. Model outputs are compared with data from coffee in Costa Rica, watermelon and sunflower in California and watermelon in New Jersey–Pennsylvania (NJPA).

Key Results

Results from Costa Rica and California, comparing field estimates of pollinator abundance, richness or services with model estimates, are encouraging, explaining up to 80 % of variance among farms. However, the model did not predict observed pollinator abundances on NJPA, so continued model improvement and testing are necessary. The inability of the model to predict pollinator abundances in the NJPA landscape may be due to not accounting for fine-scale floral and nesting resources within the landscapes surrounding farms, rather than the logic of our model.

Conclusions

The importance of fine-scale resources for pollinator service delivery was supported by sensitivity analyses indicating that the model''s predictions depend largely on estimates of nesting and floral resources within crops. Despite the need for more research at the finer-scale, the approach fills an important gap by providing quantitative and mechanistic model from which to evaluate policy decisions and develop land-use plans that promote pollination conservation and service delivery.Key words: Agriculture, bees, ecosystem services, landscape ecology, model, land use, pollinators     

Microclimate and limits to photosynthesis in a diverse community of hypolithic cyanobacteria in northern Australia

Hypolithic microbes, primarily cyanobacteria, inhabit the highly specialized microhabitats under translucent rocks in extreme environments. Here we report findings from hypolithic cyanobacteria found under three types of translucent rocks (quartz, prehnite, agate) in a semiarid region of tropical Australia. We investigated the photosynthetic responses of the cyanobacterial communities to light, temperature and moisture in the laboratory, and we measured the microclimatic variables of temperature and soil moisture under rocks in the field over an annual cycle. We also used molecular techniques to explore the diversity of hypolithic cyanobacteria in this community and their phylogenetic relationships within the context of hypolithic cyanobacteria from other continents. Based on the laboratory experiments, photosynthetic activity required a minimum soil moisture of 15% (by mass). Peak photosynthetic activity occurred between approximately 8°C and 42°C, though some photosynthesis occurred between ?1°C and 51°C. Maximum photosynthesis rates also occurred at light levels of approximately 150–550 μmol m^?2 s^?1. We used the field microclimatic data in conjunction with these measurements of photosynthetic efficiency to estimate the amount of time the hypolithic cyanobacteria could be photosynthetically active in the field. Based on these data, we estimated that conditions were appropriate for photosynthetic activity for approximately 942 h (～75 days) during the year. The hypolithic cyanobacteria community under quartz, prehnite and agate rocks was quite diverse both within and between rock types. We identified 115 operational taxonomic units (OTUs), with each rock hosting 8–24 OTUs. A third of the cyanobacteria OTUs from northern Australia grouped with Chroococcidiopsis, a genus that has been identified from hypolithic and endolithic communities from the Gobi, Mojave, Atacama and Antarctic deserts. Several OTUs identified from northern Australia have not been reported to be associated with hypolithic communities previously.     

Regulation of cell adhesion to collagen via β1 integrins is dependent on interactions of filamin A with vimentin and protein kinase C epsilon

Cell adhesion and spreading on collagen, which are essential processes for development and wound healing in mammals, are mediated by β1 integrins and the actin and intermediate filament cytoskeletons. The mechanisms by which these separate cytoskeletal systems interact to regulate β1 integrins and cell spreading are poorly defined. We previously reported that the actin cross-linking protein filamin A binds the intermediate filament protein vimentin and that these two proteins co-regulate cell spreading. Here we used deletional mutants of filamin A to define filamin A-vimentin interactions and the subsequent phosphorylation and re-distribution of vimentin during cell spreading on collagen. Imaging of fixed and live cell preparations showed that phosphorylated vimentin is translocated to the cell membrane during spreading. Knockdown of filamin A inhibited cell spreading and the phosphorylation and re-distribution of vimentin. Knockdown of filamin A and/or vimentin reduced the cell surface expression and activation of β1 integrins, as indicated by immunoblotting of plasma membrane-associated proteins and shear force assays. In vitro pull-down assays using filamin A mutants showed that both vimentin and protein kinase C? bind to repeats 1-8 of filamin A. Reconstitution of filamin-A-deficient cells with full-length filamin A or filamin A repeats 1-8 restored cell spreading, vimentin phosphorylation, and the cell surface expression of β1 integrins. We conclude that the binding of filamin A to vimentin and protein kinase Cε is an essential regulatory step for the trafficking and activation of β1 integrins and cell spreading on collagen.     

Targeting head and neck tumoral stem cells: From biological aspects to therapeutic perspectives

Head and neck squamous cell cancer(HNSCC) is the sixth most common cancer in the world. Effective therapeutic modalities such as surgery, radiation, chemotherapy and combinations of each are used in the management of the disease. In most cases, treatment fails to obtain total cancer cure. In recent years, it appears that one of the key determinants of treatment failure may be the presence of cancer stem cells(CSCs) that escape currently available therapies. CSCs form a small portion of the total tumor burden but may play a disproportionately important role in determining outcomes. CSCs have stem features such as self-renewal, high migration capacity, drug resistance, high proliferation abilities. A large body of evidence points to the fact that CSCs are particularly resistant to radiotherapy and chemotherapy. In HNSCC, CSCs have been increasingly shown to have an integral role in tumor initiation, disease progression, metastasis and treatment resistance. In the light of such observations, the present review summarizes biological characteristics of CSCs in HNSCC, outlines targeted strategies for the successful eradication of CSCs in HNSCC including targeting the self-renewal controlling pathways, blocking epithelial mesenchymal transition, niche targeting, immunotherapy approaches and highlights the need to better understand CSCs biology for new treatments modalities.     

Particulate matter exposure induces persistent lung inflammation and endothelial dysfunction

Epidemiologic and animal studies have shown that exposure to particulate matter air pollution (PM) is a risk factor for the development of atherosclerosis. Whether PM-induced lung and systemic inflammation is involved in this process is not clear. We hypothesized that PM exposure causes lung and systemic inflammation, which in turn leads to vascular endothelial dysfunction, a key step in the initiation and progression of atherosclerosis. New Zealand White rabbits were exposed for 5 days (acute, total dose 8 mg) and 4 wk (chronic, total dose 16 mg) to either PM smaller than 10 mum (PM(10)) or saline intratracheally. Lung inflammation was quantified by morphometry; systemic inflammation was assessed by white blood cell and platelet counts and serum interleukin (IL)-6, nitric oxide, and endothelin levels. Endothelial dysfunction was assessed by vascular response to acetylcholine (ACh) and sodium nitroprusside (SNP). PM(10) exposure increased lung macrophages (P<0.02), macrophages containing particles (P<0.001), and activated macrophages (P<0.006). PM(10) increased serum IL-6 levels in the first 2 wk of exposure (P<0.05) but not in weeks 3 or 4. PM(10) exposure reduced ACh-related relaxation of the carotid artery with both acute and chronic exposure, with no effect on SNP-induced vasodilatation. Serum IL-6 levels correlated with macrophages containing particles (P=0.043) and ACh-induced vasodilatation (P=0.014 at week 1, P=0.021 at week 2). Exposure to PM(10) caused lung and systemic inflammation that were both associated with vascular endothelial dysfunction. This suggests that PM-induced lung and systemic inflammatory responses contribute to the adverse vascular events associated with exposure to air pollution.     

High water users can be drought tolerant: using physiological traits for green roof plant selection

Background and aims

Green roofs are often installed to reduce urban stormwater runoff. To optimally achieve this, green roof plants need to use water when available, but reduce transpiration when limited to ensure survival. Succulent species commonly planted on green roofs do not achieve this. Water availability on green roofs is analogous to natural shallow-soil habitats including rock outcrops. We aimed to determine whether granite outcrop species could improve green roof performance by evaluating water use strategies under contrasting water availability.

Methods

Physiological and morphological responses of 12 granite outcrop species with different life-forms (monocots, herbs and shrubs) and a common green roof succulent were compared in well watered (WW) and water deficit (WD) treatments.

Key results

Granite outcrop species showed a variety of water-use strategies. Unlike the green roof succulent all of the granite outcrop species showed plasticity in water use. Monocot and herb species showed high water use under WW but also high water status under WD. This was achieved by large reductions in transpiration under WD. Maintenance of water status was also related to high root mass fraction.

Conclusions

By developing a conceptual model using physiological traits we were able to select species suitable for green roofs. The ideal species for green roofs were high water users which were also drought tolerant.     

Identification, cloning, and functional expression of three glutathione transferase genes from Aspergillus fumigatus

Analysis of the genome of the human pathogen, Aspergillus fumigatus, revealed the presence of several putative glutathione transferase (GST) open reading frames. Three A. fumigatus GST genes, termed gstA, B, and C, were cloned and recombinant proteins expressed in Escherichia coli. Functional analysis of recombinant gstA-C confirms that the enzymes exhibit GST activity and glutathione peroxidase activity. RT-PCR confirmed low basal expression of gstA and gstC which was markedly up-regulated (at least 4x-10x) in the presence of either H2O2 or 1-chloro-2,4-dinitrobenzene (CDNB). GstB expression was only observed in the presence of CDNB. These results demonstrate for the first time the existence of three functional GSTs in A. fumigatus and strongly suggest a role for these enzymes in the response of the organism to both oxidative stress and xenobiotic presence.     

Metabolic engineering of Escherichia coli for 1-butanol production

Compared to ethanol, butanol offers many advantages as a substitute for gasoline because of higher energy content and higher hydrophobicity. Typically, 1-butanol is produced by Clostridium in a mixed-product fermentation. To facilitate strain improvement for specificity and productivity, we engineered a synthetic pathway in Escherichia coli and demonstrated the production of 1-butanol from this non-native user-friendly host. Alternative genes and competing pathway deletions were evaluated for 1-butanol production. Results show promise for using E. coli for 1-butanol production.