A twenty-two-fold increase in the relative affinity of estrogen receptor to poly (dA-dC).poly (dG-dT) in the presence of polyamines.

We studied the relative efficacy of polyamines to facilitate the binding of estrogen receptor to poly(dA-dC).poly(dG-dT). In the absence of polyamines, 1,400 micrograms/ml of this polynucleotide eluted 50% of bound estrogen receptor from DNA-cellulose. In contrast, 50% estrogen receptor was eluted by 65 micrograms/ml of poly(dA-dC).poly(dG-dT) complexed with 150 microM spermidine. Putrescine and spermine also enhanced the ability of poly(dA-dC).poly(dG-dT) to elute estrogen receptor, but the magnitude of the effect was not as high as that of spermidine. Control experiments with calf thymus DNA and poly(dA-dT).poly(dA-dT) showed 6- and 3-fold increase, respectively in their affinity for estrogen receptor in the presence of spermidine. The dramatic increase in the affinity of poly(dA-dC).poly(dG-dT) for estrogen receptor in the presence of polyamines might be a result of the conversion of the polynucleotide to the left-handed Z-DNA form. These results show that polyamines are capable of participating in estrogenic regulation of gene expression by altering the affinity of the receptor for specific DNA sequences.     

Cell signaling and heat shock protein expression

Exposure of cells and organs to heat shock is associated with numerous changes in various cellular metabolic parameters and overexpression of proteins collectively known as heat shock proteins (HSP). In this communication we review the cell-signaling events that are altered in response to heat shock as they relate to the subsequent induction of HSP 70 kd (HSP-70) expression. We also review the mechanisms by which HSP-70 is involved in conferring cytoprotective effects. The possibility of altering HSP expression through manipulations of the cell-signal process has clinical importance.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army or Department of Defense.     

A highly conserved nuclear gene for low-level phylogenetics: elongation factor-1 alpha recovers morphology-based tree for heliothine moths

Molecular systematists need increased access to nuclear genes. Highly conserved, low copy number protein-encoding nuclear genes have attractive features for phylogenetic inference but have heretofore been applied mostly to very ancient divergences. By virtue of their synonymous substitutions, such genes should contain a wealth of information about lower-level taxonomic relationships as well, with the advantage that amino acid conservatism makes both alignment and primer definition straightforward. We tested this postulate for the elongation factor-1 alpha (EF-1 alpha) gene in the noctuid moth subfamily Heliothinae, which has probably diversified since the middle Tertiary. We sequenced 1,240 bp in 18 taxa representing heliothine groupings strongly supported by previous morphological and allozyme studies. The single most parsimonious gene tree and the neighbor-joining tree for all nucleotides show almost complete concordance with the morphological tree. Homoplasy and pairwise divergence levels are low, transition/transversion ratios are high, and phylogenetic information is spread evenly across gene regions. The EF-1 alpha gene and presumably other highly conserved genes hold much promise for phylogenetics of Tertiary age eukaryote groups.      

Aromatization of androgens by human breast cancer.

The metabolism of dehydroepiandrosterone and testosterone by human mammary tumor was investigated. Estrogen synthesis from dehydroepiandrosterone was observed in 9 of 10 estrogen-receptor-negative tumors and only in 2 of 8 receptor-positive tumors (p less than 0.025). Conversion of testosterone to estrogens was observed in 7 of 8 receptor-negative and 2 of 7 receptor-positive tumors. Tumors which are capable of transforming dehydroepiandrosterone to estrogens were also able to aromatize testosterone suggesting that the presence of the aromatase enzyme is inherent to certain tumor cells. No estrogen formation was detected by the mitochondrial-microsomal fraction of normal breast cells while fractions from both fat cell and tumor cell showed estrogen synthesis. Estrogen formation by tumor cell fraction ranged from 5 to 190 times that observed for fat cells. The physiological significance of these results in the neoplastic tissue and its relationship to hormone dependence are discussed.     

Effects of Surface Plasmon Coupling on the Whispering-Gallery Resonance in a Hexagonal Nanowire Cavity Structure

Plasmonics - The effects of surface plasmon (SP) coupling with the excitation radiating dipole on the behaviors of the whispering-gallery resonance (WGR) modes in a hexagonal GaN nanowire cavity...     

Critical considerations for the development of potency tests for therapeutic applications of mesenchymal stromal cell-derived small extracellular vesicles

Mesenchymal stromal/stem cells (MSCs) have been widely tested against many diseases, with more than 1000 registered clinical trials worldwide. Despite many setbacks, MSCs have been approved for the treatment of graft-versus-host disease and Crohn disease. However, it is increasingly clear that MSCs exert their therapeutic functions in a paracrine manner through the secretion of small extracellular vesicles (sEVs) of 50–200 nm in diameter. Unlike living cells that can persist long-term, sEVs are non-living and non-replicative and have a transient presence in the body. Their small size also renders sEV preparations highly amenable to sterilization by filtration. Together, acellular MSC-sEV preparations are potentially safer and easier to translate into the clinic than cellular MSC products. Nevertheless, there are inherent challenges in the development of MSC-sEV drug products. MSC-sEVs are products of living cells, and living cells are sensitive to changes in the external microenvironment. Consequently, quality control metrics to measure key identity and potency features of MSC-sEV preparations have to be specified during development of MSC-sEV therapeutics. The authors have previously described quantifiable assays to define the identity of MSC-sEVs. Here the authors discuss requirements for prospective potency assays to predict the therapeutic effectiveness of the drug substance in accordance with International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines. Although potency assays should ideally reflect the mechanism of action (MoA), this is challenging because the MoA for the reported efficacy of MSC-sEV preparations against multiple diseases of diverse underlying pathology is likely to be complex and different for each disease and difficult to fully elucidate. Nevertheless, robust potency assays could be developed by identifying the EV attribute most relevant to the intended biological activity in EV-mediated therapy and quantifying the EV attribute. Specifically, the authors highlight challenges and mitigation measures to enhance the manufacture of consistent and reproducibly potent sEV preparations, to identify and select the appropriate EV attribute for potency assays despite a complex “work-in-progress” MoA and to develop assays likely to be compliant with regulatory guidance for assay validation.     

Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Radioprotective effects of oral 17-dimethylaminoethylamino-17-demethoxygeldanamycin in mice: bone marrow and small intestine

Background

Our previous research demonstrated that one subcutaneous injection of 17-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) 24 hours (h) before irradiation (8.75 Gy) increased mouse survival by 75%. However, the protective mechanism of 17-DMAG is currently unknown. The present study aimed to investigate whether oral administration of 17-DMAG was also radioprotective and the potential role it may play in radioprotection.

Results

A single dose of orally pre-administered (24, 48, or 72 h) 17-DMAG (10 mg/kg) increased irradiated mouse survival, reduced body weight loss, improved water consumption, and decreased facial dropsy, whereas orally post-administered 17-DMAG failed. Additional oral doses of pre-treatment did not improve 30-day survival. The protective effect of multiple pre-administrations (2?3 times) of 17-DMAG at 10 mg/kg was equal to the outcome of a single pre-treatment. In 17-DMAG-pretreated mice, attenuation of bone marrow aplasia in femurs 30 days after irradiation with recovered expressions of cluster of differentiation 34, 44 (CD34, CD44), and survivin in bone marrow cells were observed. 17-DMAG also elevated serum granulocyte-colony stimulating factor (G-CSF), decreased serum fms-related tyrosine kinase 3 ligand, and reduced white blood cell depletion. 17-DMAG ameliorated small intestinal histological damage, promoted recovery of villus heights and intestinal crypts including stem cells, where increased leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) was found 30 days after irradiation.

Conclusions

17-DMAG is a potential radioprotectant for bone marrow and small intestine that results in survival improvement.

     

Coupling Behaviors of Surface Plasmon Polariton and Localized Surface Plasmon with an InGaN/GaN Quantum Well

Plasmonics - Surface plasmon (SP) coupling behaviors of an InGaN/GaN quantum well (QW) with surface plasmon polariton (SPP) induced on a smooth Ag-film/GaN interface and localized surface plasmon...