Secured secret sharing technique based on chaotic map and DNA encoding with application on secret image

This paper shows a secured key-based (k, n) threshold cryptography scheme, where key as well as secret data is shared among set of participants. In this scheme, each share has some bytes missing and these missing bytes can be recovered from a set of exactly k shares, but not less than k. Therefore, each share contains partial secret information which is also encrypted by DNA encoding scheme. Additionally, this paper introduces a concept, where each share information size is varied. More precisely, each share contains a different percentage of secret information and which is strongly dependent on the key. Moreover key sensitivity analysis and statistical analysis prove the robustness against different cryptanalysis attacks and thus ensures high acceptability for information security requirements.     

In Silico Screening Identifies a Novel Potential PARP1 Inhibitor Targeting Synthetic Lethality in Cancer Treatment

Synthetic lethality describes situations in which defects in two different genes or pathways together result in cell death. This concept has been applied to drug development for cancer treatment, as represented by Poly (ADP-ribose) polymerase (PARPs) inhibitors. In the current study, we performed a computational screening to discover new PARP inhibitors. Among the 11,247 compounds analyzed, one natural product, ZINC67913374, stood out by its superior performance in the simulation analyses. Compared with the FDA approved PARP1 inhibitor, olaparib, our results demonstrated that the ZINC67913374 compound achieved a better grid score (−86.8) and amber score (−51.42). Molecular dynamics simulations suggested that the PARP1-ZINC67913374 complex was more stable than olaparib. The binding free energy for ZINC67913374 was −177.28 kJ/mol while that of olaparib was −159.16 kJ/mol. These results indicated ZINC67913374 bound to PARP1 with a higher affinity, which suggest ZINC67913374 has promising potential for cancer drug development.     

Circulating Tumor Cells (CTC) and Cell-Free DNA (cfDNA) Workshop 2016: Scientific Opportunities and Logistics for Cancer Clinical Trial Incorporation

Despite the identification of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) as potential blood-based biomarkers capable of providing prognostic and predictive information in cancer, they have not been incorporated into routine clinical practice. This resistance is due in part to technological limitations hampering CTC and cfDNA analysis, as well as a limited understanding of precisely how to interpret emergent biomarkers across various disease stages and tumor types. In recognition of these challenges, a group of researchers and clinicians focused on blood-based biomarker development met at the Canadian Cancer Trials Group (CCTG) Spring Meeting in Toronto, Canada on 29 April 2016 for a workshop discussing novel CTC/cfDNA technologies, interpretation of data obtained from CTCs versus cfDNA, challenges regarding disease evolution and heterogeneity, and logistical considerations for incorporation of CTCs/cfDNA into clinical trials, and ultimately into routine clinical use. The objectives of this workshop included discussion of the current barriers to clinical implementation and recent progress made in the field, as well as fueling meaningful collaborations and partnerships between researchers and clinicians. We anticipate that the considerations highlighted at this workshop will lead to advances in both basic and translational research and will ultimately impact patient management strategies and patient outcomes.     

Mechanisms of Cell Killing Response from Low Linear Energy Transfer (LET) Radiation Originating from 177Lu Radioimmunotherapy Targeting Disseminated Intraperitoneal Tumor Xenografts

Radiolabeled antibodies (mAbs) provide efficient tools for cancer therapy. The combination of low energy β⁻-emissions (500 keV_max; 130 keV_ave) along with a γ-emission for imaging makes ¹⁷⁷Lu (T_1/2 = 6.7 day) a suitable radionuclide for radioimmunotherapy (RIT) of tumor burdens possibly too large to treat with α-particle radiation. RIT with ¹⁷⁷Lu-trastuzumab has proven to be effective for treatment of disseminated HER2 positive peritoneal disease in a pre-clinical model. To elucidate mechanisms originating from this RIT therapy at the molecular level, tumor bearing mice (LS-174T intraperitoneal xenografts) were treated with ¹⁷⁷Lu-trastuzumab comparatively to animals treated with a non-specific control, ¹⁷⁷Lu-HuIgG, and then to prior published results obtained using ²¹²Pb-trastuzumab, an α-particle RIT agent. ¹⁷⁷Lu-trastuzumab induced cell death via DNA double strand breaks (DSB), caspase-3 apoptosis, and interfered with DNA-PK expression, which is associated with the repair of DNA non-homologous end joining damage. This contrasts to prior results, wherein ²¹²Pb-trastuzumab was found to down-regulate RAD51, which is involved with homologous recombination DNA damage repair. ¹⁷⁷Lu-trastuzumab therapy was associated with significant chromosomal disruption and up-regulation of genes in the apoptotic process. These results suggest an inhibition of the repair mechanism specific to the type of radiation damage being inflicted by either high or low linear energy transfer radiation. Understanding the mechanisms of action of β⁻- and α-particle RIT comparatively through an in vivo tumor environment offers real information suitable to enhance combination therapy regimens involving α- and β⁻-particle RIT for the management of intraperitoneal disease.     

Temperature dependence of transfer characteristics of OTFT memory based on DNA-CTMA gate dielectric

A nonvolatile memory based on an organic thin-film transistor (OTFT) with a biopolymer of DNA-cetyltrimethylammonium chloride (DNA-CTMA) acting as the gate dielectric layer was fabricated. The transfer characteristics of the device prepared by both DNA alone and DNA-CTMA showed a very large and stable hysteresis. In order to analyze the memory mechanism, the temperature dependence of the transfer characteristics, electric conductivity, differential scanning calorimetry (DSC), thermally stimulated depolarization current (TSDC) as well as the dielectric property of the DNA-CTMA film have been investigated. As a result, the quasi-ferroelectric polarization originating from the alignment of the intrinsic dipole moment inside the DNA-CTMA complex was identified as the main source of hysteresis in the lower temperature region.     

Barosensitivity in Saccharomyces cerevisiae is Closely Associated with a Deletion of the COX1 Gene

High hydrostatic pressure causes physical stress to microorganisms; therefore, this technology may be applied to food pasteurization without introducing the unfavorable effects of thermal denaturation. However, its application is limited to high‐value foods because the treatment requires a robust steel vessel and expensive pressurization equipment. To reduce these costs, we studied the pasteurization of Saccharomyces cerevisiae using relatively moderate high‐pressure levels. A mutant strain isolated by ultraviolet mutagenesis showed significant loss of viability under high‐pressure conditions. Gene expression analysis of the mutant strain revealed that it incurred a deletion of the COX1 gene. Our results suggest that the pressure‐sensitivity can readily be introduced into industrial/food microorganisms by complementing a COX1 deleted mitochondria.     

Molecular Identification of Dendrobium Species (Orchidaceae) Based on the DNA Barcode ITS2 Region and Its Application for Phylogenetic Study

The over-collection and habitat destruction of natural Dendrobium populations for their commercial medicinal value has led to these plants being under severe threat of extinction. In addition, many Dendrobium plants are similarly shaped and easily confused during the absence of flowering stages. In the present study, we examined the application of the ITS2 region in barcoding and phylogenetic analyses of Dendrobium species (Orchidaceae). For barcoding, ITS2 regions of 43 samples in Dendrobium were amplified. In combination with sequences from GenBank, the sequences were aligned using Clustal W and genetic distances were computed using MEGA V5.1. The success rate of PCR amplification and sequencing was 100%. There was a significant divergence between the inter- and intra-specific genetic distances of ITS2 regions, while the presence of a barcoding gap was obvious. Based on the BLAST1, nearest distance and TaxonGAP methods, our results showed that the ITS2 regions could successfully identify the species of most Dendrobium samples examined; Second, we used ITS2 as a DNA marker to infer phylogenetic relationships of 64 Dendrobium species. The results showed that cluster analysis using the ITS2 region mainly supported the relationship between the species of Dendrobium established by traditional morphological methods and many previous molecular analyses. To sum up, the ITS2 region can not only be used as an efficient barcode to identify Dendrobium species, but also has the potential to contribute to the phylogenetic analysis of the genus Dendrobium.     

Generation of Rho Zero Cells: Visualization and Quantification of the mtDNA Depletion Process

Human mitochondrial DNA (mtDNA) is located in discrete DNA-protein complexes, so called nucleoids. These structures can be easily visualized in living cells by utilizing the fluorescent stain PicoGreen^®. In contrary, cells devoid of endogenous mitochondrial genomes (ρ⁰ cells) display no mitochondrial staining in the cytoplasm. A modified restriction enzyme can be targeted to mitochondria to cleave the mtDNA molecules in more than two fragments, thereby activating endogenous nucleases. By applying this novel enzymatic approach to generate mtDNA-depleted cells the destruction of mitochondrial nucleoids in cultured cells could be detected in a time course. It is clear from these experiments that mtDNA-depleted cells can be seen as early as 48 h post-transfection using the depletion system. To prove that mtDNA is degraded during this process, mtDNA of transfected cells was quantified by real-time PCR. A significant decline could be observed 24 h post-transfection. Combination of both results showed that mtDNA of transfected cells is completely degraded and, therefore, ρ⁰ cells were generated within 48 h. Thus, the application of a mitochondrially-targeted restriction endonuclease proves to be a first and fast, but essential step towards a therapy for mtDNA disorders.     

A multiplex-conventional PCR assay for bovine,ovine, caprine and fish species identification in feedstuffs: Highly sensitive and specific

A multiplex PCR assay was developed for rapid and reliable identification of bovine, ovine, caprine and fish species in feedstuffs simultaneously. The method merges the use of bovine, ovine, caprine and fish primers that amplify fragments (ovine; 119 bp, caprine; 142 bp, fish; 224 bp and bovine; 271 bp) of the mitochondrial t.glu gene forward and cyt b reverse, 12S rRNA, 12S rRNA, and ATPase subunit 8 genes respectively, and a universal 18S rRNA primers that amplifies a 99 bp from eukaryotic DNA. To evaluate the effect of heat treatment, a severe sterilization condition (133 °C at 300 kPa for 20 min) was applied. Multiplex analysis of the reference feedstuff samples showed that the detection limit of the assay was 0.01% for each species. Taken together, all data indicated that this multiplex PCR assay was a simple, rapid, sensitive, specific, and cost-effective detection method for bovine, ovine, caprine and fish species in feedstuffs.