Design and characterization of electrochemical dopamine–aptamer as convenient and integrated sensing platform

Here, an ultrasensitive label-free electrochemical aptasensor was developed for dopamine (DA) detection. Construction of the aptasensor was carried out by electrodeposition of gold–platinum nanoparticles (Au–PtNPs) on glassy carbon (GC) electrode modified with acid-oxidized carbon nanotubes (CNTs–COOH). A designed complementary amine-capped capture probe (ssDNA1) was immobilized at the surface of PtNPs/CNTs–COOH/GC electrode through the covalent amide bonds formed by the carboxyl groups on the nanotubes and the amino groups on the oligonucleotides. DA-specific aptamer was attached onto the electrode surface through hybridization with the ssDNA1. Methylene blue (MB) was used as an electrochemical indicator that was intercalated into the aptamer through the specific interaction with its guanine bases. In the presence of DA, the interaction between aptamer and DA displaced the MB from the electrode surface, rendering a lowered electrochemical signal attributed to a decreased amount of adsorbed MB. This phenomenon can be applied for DA detection. The peak current of probe (MB) linearly decreased over a DA concentration range of 1–30 nM with a detection limit of 0.22 nM.     

Genomic comparison between members of the Salinibacteraceae family,and description of a new species of Salinibacter (Salinibacter altiplanensis sp. nov.) isolated from high altitude hypersaline environments of the Argentinian Altiplano

The application of tandem MALDI-TOF MS screening with 16S rRNA gene sequencing of selected isolates has been demonstrated to be an excellent approach for retrieving novelty from large-scale culturing. The application of such methodologies in different hypersaline samples allowed the isolation of the culture-recalcitrant Salinibacter ruber second phylotype (EHB-2) for the first time, as well as a new species recently isolated from the Argentinian Altiplano hypersaline lakes. In this study, the genome sequences of the different species of the phylum Rhodothermaeota were compared and the genetic repertoire along the evolutionary gradient was analyzed together with each intraspecific variability. Altogether, the results indicated an open pan-genome for the family Salinibacteraceae, as well as the codification of relevant traits such as diverse rhodopsin genes, CRISPR-Cas systems and spacers, and one T6SS secretion system that could give ecological advantages to an EHB-2 isolate. For the new Salinibacter species, we propose the name Salinibacter altiplanensis sp. nov. (the designated type strain is AN15^T = CECT 9105^T = IBRC-M 11031^T).     

Kani: a QoS-aware hypervisor-level scheduler for cloud computing environments

Cloud computing environments (CCEs) are expected to deliver their services with qualities in service level agreements. On the other hand, they typically employ virtualization technology to consolidate multiple workloads on the same physical machine, thereby enhancing the overall utilization of physical resources. Most existing virtualization technologies are, however, unaware of their delivered quality of services (QoS). For example, the Xen hypervisor merely focuses on fair sharing of processor resources. We believe that CCEs have got married with traditional virtualization technologies without many traits in common. To bridge the gap between these two technologies, we have designed and implemented Kani, a QoS-aware hypervisor-level scheduler. Kani dynamically monitors the quality of delivered services to quantify the deviation between desired and delivered levels of QoS. Using this information, Kani determines how to allocate processor resources among running VMs so as to meet the expected QoS. Our evaluations of Kani scheduler prototype in Xen show that Kani outperforms the default Xen scheduler namely the Credit scheduler. For example, Kani reduces the average response time to requests to an Apache web server by up to \(93.6\,\%\); improves its throughput by up to \(97.9\,\%\); and mitigates the call setup time of an Asterisk media server by up to \(96.6\,\%\).     

Dielectric properties of tissues; variation with age and their relevance in exposure of children to electromagnetic fields; state of knowledge

This paper reviews and summarises the state of knowledge on dielectric properties of tissues; in particular those obtained as a function of age. It also examines the impact of variation in dielectric data on the outcome of recent dosimetric studies assessing the exposure of children to electromagnetic fields.     

An improved method for extraction of high-quality total RNA from oil seeds

Biotechnology Letters - Seeds of oilseed plants that contain large amounts of oil, polysaccharides, proteins and polyphenols are not amenable to conventional RNA isolation protocols. The presence...     

A Review of the Chemistry and Biological Activities of Natural Colorants,Dyes, and Pigments: Challenges,and Opportunities for Food,Cosmetics, and Pharmaceutical Application

Natural pigments are important sources for the screening of bioactive lead compounds. This article reviewed the chemistry and therapeutic potentials of over 570 colored molecules from plants, fungi, bacteria, insects, algae, and marine sources. Moreover, related biological activities, advanced extraction, and identification approaches were reviewed. A variety of biological activities, including cytotoxicity against cancer cells, antioxidant, anti-inflammatory, wound healing, anti-microbial, antiviral, and anti-protozoal activities, have been reported for different pigments. Considering their structural backbone, they were classified as naphthoquinones, carotenoids, flavonoids, xanthones, anthocyanins, benzotropolones, alkaloids, terpenoids, isoprenoids, and non-isoprenoids. Alkaloid pigments were mostly isolated from bacteria and marine sources, while flavonoids were mostly found in plants and mushrooms. Colored quinones and xanthones were mostly extracted from plants and fungi, while colored polyketides and terpenoids are often found in marine sources and fungi. Carotenoids are mostly distributed among bacteria, followed by fungi and plants. The pigments isolated from insects have different structures, but among them, carotenoids and quinone/xanthone are the most important. Considering good manufacturing practices, the current permitted natural colorants are: Carotenoids (canthaxanthin, β-carotene, β-apo-8′-carotenal, annatto, astaxanthin) and their sources, lycopene, anthocyanins, betanin, chlorophyllins, spirulina extract, carmine and cochineal extract, henna, riboflavin, pyrogallol, logwood extract, guaiazulene, turmeric, and soy leghemoglobin.     

Cellulose nanocrystals from celery stalk as quercetin scaffolds: A novel perspective of human holo-transferrin adsorption and digestion behaviours

In this study, cellulose nanocrystals (CNCs) were synthesized from celery stalks to be used as the platform for quercetin delivery. Additionally, CNCs and CNCs–quercetin were characterized using the results of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and zeta potential, while their interactions with human holo-transferrin (HTF) were also investigated. We examined their interaction under physiological conditions through the exertion of fluorescence, resonance light scattering, synchronized fluorescence spectroscopy, circular dichroism, three-dimensional fluorescence spectroscopy, and fluorescence resonance energy transfer techniques. The data from SEM and TEM exhibited the spherical shape of CNCs and CNCs–quercetin and also, a decrease was detected in the size of quercetin-loaded CNCs from 676 to 473 nm that indicated the intensified water solubility of quercetin. The success of cellulose acid hydrolysis was confirmed based on the XRD results. Apparently, the crystalline index of CNCs–quercetin was reduced by the interaction of CNCs with quercetin, which also resulted in the appearance of functional groups, as shown by FTIR. The interaction of CNCs–quercetin with HTF was also demonstrated by the induced quenching in the intensity of HTF fluorescence emission and Stern–Volmer data represent the occurrence of static quenching. Overall, the effectiveness of CNCs as quercetin vehicles suggests its potential suitability for dietary supplements and pharmaceutical products.     

Antitumor effect of therapeutic HPV DNA vaccines with chitosan-based nanodelivery systems

Background

Cervical cancer is the second-most-common cause of malignancies in women worldwide, and the oncogenic activity of the human papilloma virus types (HPV) E7 protein has a crucial role in anogenital tumors. In this study, we have designed a therapeutic vaccine based on chitosan nanodelivery systems to deliver HPV-16 E7 DNA vaccine, considered as a tumor specific antigen for immunotherapy of HPV-associated cervical cancer. We have developed a Nano-chitosan (NCS) as a carrier system for intramuscular administration using a recombinant DNA vaccine expressing HPV-16 E7 (NCS-DNA E7 vaccine). NCS were characterized in vitro for their gene transfection ability.

Results

The transfection of CS-pEGFP NPs was efficient in CHO cells and the expression of green fluorescent proteins was well observed. In addition, NCS-DNA E7 vaccine induced the strongest E7-specific CD8+ T cell and interferon γ responses in C57BL/6 mice. Mice vaccinated with NCS-DNA E7 vaccine were able to generate potent protective and therapeutic antitumor effects against challenge with E7-expressing tumor cell line, TC-1.

Conclusions

The strong therapeutic effect induced by the Chitosan-based nanodelivery suggest that nanoparticles may be an efficient carrier to improve the immunogenicity of DNA vaccination upon intramuscular administration and the platform could be further exploited as a potential cancer vaccine candidate in humans.