DNA Nano-Gears

DNA is a nanoscale material for programmable self-assembly, using the selective affinity of pairs of DNA strands to form DNA nanostructures. Self-assembly is the spontaneous self-ordering of substructures into superstructures which driven by the selective affinity of the substructures. DNA self-assembly is the most advanced and versatile system that has been experimentally demonstrated for programmable construction of patterned systems on the molecular scale. This programmability renders the scaffolding have the patterning required for fabricating complex devices made of these components. We present various strategies to assemble DNA based gears for application in nano-machines, nano-motors and nano-devices. In this paper, some fundamental parts of mechanical nano-machines with DNA blocks are designed. These kinds of nanostructures, nano-gears, are fundamental for the development of future useful molecular-level devices.     

The effect of spent mushroom compost on Lecanicillium fungicola in vivo and in vitro

Leached spent mushroom compost (SMC) and its extract were tested to suppress Lecanicillium fungicola in white button mushroom. Sterile and non-sterile mixture of SMC and peat were used to assess suppressiveness against L. fungicola in greenhouse experiments. The extract of SMC was prepared with sterile, non-sterile, filtered, supplied with nystatin, streptomycin and penicillin antibiotics to evaluate their effect in suppression of pathogen in vitro. Isolated bacteria from SMC extract were tested for antagonism rate against Lecanicillium fungicola. The results of the experiments showed that all applications rate of none-sterile SMC were effective in control of pathogen. However, the sterile SMC amendments did not have a positive effect on the pathogen suppression in vitro or in vivo, as was expected. The treatments amended with SMC 100% and 60% showed the most suppressive effect in the control of pathogen. Using of non-sterile SMC 20%, 40%, 60% and peat soil were most effective in mushroom yield. The extract of leached SMC showed inhibition of L. fungicola in petri dishes. Three bacteria isolated from extract, Bacillus subtilis, Bacillus licheniformis and Bacillus amyloliquefacien identified using 16s rRNA, showed an antagonistic effect with the fungal growth.     

Inhibition of the Receptor Tyrosine Kinase ROR1 by Anti-ROR1 Monoclonal Antibodies and siRNA Induced Apoptosis of Melanoma Cells

The receptor tyrosine kinase (RTK) ROR1 is overexpressed and of importance for the survival of various malignancies, including lung adenocarcinoma, breast cancer and chronic lymphocytic leukemia (CLL). There is limited information however on ROR1 in melanoma. In the present study we analysed in seven melanoma cell lines ROR1 expression and phosphorylation as well as the effects of anti-ROR1 monoclonal antibodies (mAbs) and ROR1 suppressing siRNA on cell survival. ROR1 was overexpressed at the protein level to a varying degree and phosphorylated at tyrosine and serine residues. Three of our four self-produced anti-ROR1 mAbs (clones 3H9, 5F1 and 1A8) induced a significant direct apoptosis of the ESTDAB049, ESTDAB112, DFW and A375 cell lines as well as cell death in complement dependent cytotoxicity (CDC) and antibody dependent cellular cytotoxicity (ADCC). The ESTDAB081 and 094 cell lines respectively were resistant to direct apoptosis of the four anti-ROR1 mAbs alone but not in CDC or ADCC. ROR1 siRNA transfection induced downregulation of ROR1 expression both at mRNA and protein levels proceeded by apoptosis of the melanoma cells (ESTDAB049, ESTDAB112, DFW and A375) including ESTDAB081, which was resistant to the direct apoptotic effect of the mAbs. The results indicate that ROR1 may play a role in the survival of melanoma cells. The surface expression of ROR1 on melanoma cells may support the notion that ROR1 might be a suitable target for mAb therapy.     

Efficacy of biogenic selenium nanoparticles against Leishmania major: In vitro and in vivo studies

Project: This study investigated the in vitro and in vivo effectiveness of biogenic selenium nanoparticles (Se NPs), biosynthesized by Bacillus sp. MSh-1, against Leishmania major (MRHO/IR/75/ER). Procedure: The 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity effects of the biogenic Se NPs against both promastigote and amastigote forms of L. major. In a separate in vivo experiment, we also determined the preventive and therapeutic effects of biogenic Se NPs in BALB/c mice following subcutaneous infected with L. major. Results: The MTT assays showed that the highest toxicity occurred after 72 h against both promastigote and amastigote forms of L. major. The cytotoxicity of Se NPs was higher at all incubation times (24, 48, and 72 h) against the promastigote than the amastigote form (p < 0.05). The 50% inhibitory concentrations (IC₅₀) of the Se NPs were 1.62 ± 0.6 and 4.4 ± 0.6 μg ml^?1 against the promastigote and amastigote forms, respectively, after a 72-h incubation period. Apoptosis assays showed DNA fragmentation in promastigotes treated with Se NPs. In an animal challenge, prophylactic doses of biogenic Se NPs delayed the development of localized cutaneous lesions. Moreover, daily administration of Se NPs (5 or 10 mg kg^?1 day^?1) in similarly infected BALB/c mice that had not received prophylactic doses of Se NPs also abolished the localized lesions after 14 days. Conclusion: Based on these in vitro and in vivo studies, biogenic Se NPs can be considered as a novel therapeutic agent for treatment of the localized lesions typical of cutaneous leishmaniasis.     

An l-Arginine supplement improves broiler hypertensive response and gut function in broiler chickens reared at high altitude

An experiment was carried out to examine the effects of supplemental dietary arginine (ARG) on growth, hypertensive response, and gut function in broilers reared at high altitude (2,100 m). A total of 120 day-old male broilers (Cobb 500) were divided equally into two treatment groups. Treatments included a control basal diet composed of corn and soybean meal and an experimental diet to which an l-ARG supplement was added at 10 g/kg. The trial lasted for 42 days. There were no treatment differences with regard to feed intake, body weight gain, or feed conversion ratio. However ARG supplementation did increase the plasma concentration of nitric oxide, a potent vasodilator (P?<?0.05), and attenuated indices of pulmonary hypertension as reflected by reductions in the hematocrit and the right to total ventricular weight ratio (P?<?0.05). Significantly enhanced intestinal mucosal development was observed in broilers receiving ARG supplement when compared with controls (P?<?0.05), suggesting that ARG supplementation increased the absorptive surface area of the jejunum and ileum. In conclusion, broiler diets supplemented with ARG beneficially improved pulmonary hemodynamics and appeared to enhance gut function.     

Recent advances in hydrogen peroxide imaging for biological applications

Mounting evidence supports the role of hydrogen peroxide (H₂O₂) in physiological signaling as well as pathological conditions. However, the subtleties of peroxide-mediated signaling are not well understood, in part because the generation, degradation, and diffusion of H₂O₂ are highly volatile within different cellular compartments. Therefore, the direct measurement of H₂O₂ in living specimens is critically important. Fluorescent probes that can detect small changes in H₂O₂ levels within relevant cellular compartments are important tools to study the spatial dynamics of H₂O₂. To achieve temporal resolution, the probes must also be photostable enough to allow multiple readings over time without loss of signal. Traditional fluorescent redox sensitive probes that have been commonly used for the detection of H₂O₂ tend to react with a wide variety of reactive oxygen species (ROS) and often suffer from photostablilty issues. Recently, new classes of H₂O₂ probes have been designed to detect H₂O₂ with high selectivity. Advances in H₂O₂ measurement have enabled biomedical scientists to study H₂O₂ biology at a level of precision previously unachievable. In addition, new imaging techniques such as two-photon microscopy (TPM) have been employed for H₂O₂ detection, which permit real-time measurements of H₂O₂in vivo. This review focuses on recent advances in H₂O₂ probe development and optical imaging technologies that have been developed for biomedical applications.