Dispersion-Assisted Tunable Fluorescence from Carbon Dots

In this study, carbon dots (CDs) synthesized by hydrothermal method with amino-rich surface exhibit tunable fluorescence across entire visible range by simply controlling the concentration. A comprehensive comparison has been performed for the first time between concentration-induced aggregation of the single-type CDs and electrostatic-induced agglomeration of opposite-charged CDs in terms of their fluorescence properties. Experimental results show that both the aggregation of CDs and internal absorption filtration are possible causes of the concentration-dependent fluorescence emission. Subsequently, the inter distance of adjacent CDs in their aggregates was enlarged by forming rigid double-stranded DNA (dsDNA) between adjacent CDs through base pairing. It is clear that the contact of CDs induces the changes of fluorescence emission and light absorption. Through a better understanding of the mechanisms behind concentration-induced multicolor emission, this work can provide a novel strategy to develop the advanced applications of CDs.

Design, Synthesis, and Docking Studies of Arylhydrazone Compounds and Evaluation of Their Platelet Aggregation Inhibitory Effect and Cytotoxicity

In view of proven antiplatelet activity of hydrazone group containing compounds, two series of hydrazone derivatives were synthesized by coupling appropriate aldehydes with phenyl hydrazine and Isonicotinic acid in the presence of distilled water and a catalytic amount of glacial acetic acid. All synthesized compounds were screened for their antiplatelet activity against induced aggregation by adenosine diphosphate (ADP) and arachidonic acid (AA). The results indicate that compounds in arylhydrazone group had shown satisfactory activity. Among them, 1-(3-methoxybenzylidene)-2-phenylhydrazine (1c), 2-methoxy-4-(2-phenylhydrazono) methyl phenol (1g), and 2-((2-phenylhydrazono) methyl)-1H-pyrrole (1h) were found to be the most potent antiplatelet compounds with IC50 less than 39 μM. Furthermore, the cell toxicity assay, (MTT test) indicates their noncytotoxic in various cell lines. None of the synthesized N-isonicotinohydrazide derivatives in this study excreted sufficient antiplatelet activity.

Exploring the Mechanisms of Anti-Aβ42 Aggregation Activity of Walnut-derived Peptides using Transcriptomics and Proteomics in vitro

Inhibiting β-amyloid (Aβ) aggregation is of significance in finding potential candidates for Alzheimer’s disease (AD) treatment. Accumulating evidence suggests that nutrition is important for improving cognition and reducing AD risk. Walnut has been widely used as a functional food for brain health; however the underlying mechanisms remain unknown. Here, we investigated the molecular level alteration in Arctic mutant Aβ42 induced aggregation cell model by RNA-seq and iTRAQ approaches after walnut-derived peptides Pro-Pro-Lys-Asn-Trp (PW5) and Trp-Pro-Pro-Lys-Asn (WN5) interventions. PW5 or WN5 could significantly decrease abnormal Aβ42 aggregates. However, resultant alterations in transcriptome (substantially unchanged) were inconsistent with proteomic data (marked change). Proteomic analysis revealed 184 and 194 differentially expressed proteins unique to PW5 and WN5 treatment, respectively, for inhibiting Aβ42 protein production or increasing protein degradation via the mismatch repair pathways. Our study provides new insights into the effectiveness of food-derived peptides for anti-Aβ42 aggregation in AD.

Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A): Could It Be a Promising Biomarker and Therapeutic Target in Parkinson’s Disease?

Parkinson’s disease (PD) is an incurable neurodegenerative disease characterized by aggregation of pathological alpha-synuclein (α-syn) and loss of dopaminergic neuron in the substantia nigra. Inhibition of phosphorylation of the α-syn has been shown to mediate alleviation of PD-related pathology. Protein phosphatase 2A (PP2A), an important serine/threonine phosphatase, plays an essential role in catalyzing dephosphorylation of the α-syn. Here, we identified and validated cancerous inhibitor of PP2A (CIP2A), as a potential diagnostic biomarker for PD. Our data showed that plasma CIP2A concentrations in PD patients were significantly lower compared to age- and sex-matched controls, 1.721 (1.435–2.428) ng/ml vs 3.051(2.36–5.475) ng/ml, p < 0.0001. The area under the curve of the plasma CIP2A in distinguishing PD from the age- and sex-matched controls was 0.776. In addition, we evaluated the role of CIP2A in PD-related pathogenesis in PD cellular and MPTP-induced mouse model. The results demonstrated that CIP2A is upregulated in PD cellular and MPTP-induced mouse models. Besides, suppression of the CIP2A expression alleviates rotenone induced aggregation of the α-syn as well as phosphorylation of the α-syn in SH-SY5Y cells, which is associated with increased PP2A activity. Taken together, our data demonstrated that CIP2A plays an essential role in the mechanisms related to PD development and might be a novel PD biomarker.

Molecular Insights into the Antistress Potentials of Brazilian Green Propolis Extract and Its Constituent Artepillin C

Propolis, also known as bee-glue, is a resinous substance produced by honeybees from materials collected from plants they visit. It contains mixtures of wax and bee enzymes and is used by bees as a building material in their hives and by humans for different purposes in traditional healthcare practices. Although the composition of propolis has been shown to depend on its geographic location, climatic zone, and local flora; two largely studied types of propolis: (i) New Zealand and (ii) Brazilian green propolis have been shown to possess Caffeic Acid Phenethyl Ester (CAPE) and Artepillin C (ARC) as the main bioactive constituents, respectively. We have earlier reported that CAPE and ARC possess anticancer activities, mediated by abrogation of mortalin-p53 complex and reactivation of p53 tumor suppressor function. Like CAPE, Artepillin C (ARC) and the supercritical extract of green propolis (GPSE) showed potent anticancer activity. In this study, we recruited low doses of GPSE and ARC (that did not affect either cancer cell proliferation or migration) to investigate their antistress potential using in vitro cell based assays. We report that both GPSE and ARC have the capability to disaggregate metal- and heat-induced aggregated proteins. Metal-induced aggregation of GFP was reduced by fourfold in GPSE- as well as ARC-treated cells. Similarly, whereas heat-induced misfolding of luciferase protein showed 80% loss of activity, the cells treated with either GPSE or ARC showed 60–80% recovery. Furthermore, we demonstrate their pro-hypoxia (marked by the upregulation of HIF-1α) and neuro-differentiation (marked by differentiation morphology and upregulation of expression of GFAP, β-tubulin III, and MAP2). Both GPSE and ARC also offered significant protection against oxidative stress and, hence, may be useful in the treatment of old age-related brain pathologies.

Histidine Functionalized Gold Nanoparticles for Screening Aminoglycosides and Nanomolar Level Detection of Streptomycin in Water, Milk, and Whey

Aminoglycoside (AMG) antibiotics are being applied to treat infections caused by Gram-negative bacteria, mainly in livestock, and are prescribed only in severe cases because of their adverse impacts on human health and the environment. Monitoring antibiotic residues in dairy products relies on the accessibility of portable and efficient analytical techniques. Presently, high-throughput screening techniques have been proposed to detect several antimicrobial drugs having identical structural and functional features. The L-histidine functionalized gold nanoparticles (His@AuNPs) do not form a complex with other tested antibiotic classes but show high selectivity for AMG antibiotics. We used ligand-induced aggregation of His@AuNPs as a rapid and sensitive localized surface plasmon resonance (LSPR) assay for AMG antibiotics, producing longitudinal extinction shifts at 660 nm. Herein, we explore the practical application of His@AuNPs to detect streptomycin spiked in water, milk, and whey fraction of milk with nanomolar level sensitivity. The ability of the analytical method to recognize target analytes sensitively and rapidly is of great significance to perform monitoring, thus would certainly reassure widespread use of AMG antibiotics. The biosynthesis of hybrid organic–inorganic metal nanoparticles like His@AuNPs with desired size distribution, stability, and specific host–guest recognition proficiency, would further facilitate applications in various other fields.

Functional activity of platelets in aged patients with chronic heart failure with hyperbaric oxygenation

105 patients with chronic heart failure (CHF) with ischemic etiology of functional class were examined, among them 70 men (67%) and 35 women (33%), average age 78,67±13,80 years. A five-day course of hyperbaric oxygen treatment in the BLKS-303MK pressure chamber (Russia) in the 1.2 ATA with a 30-45 minutes session was accompanied by a study of the func-tional activity of platelets. It was found that after hyperbaric oxygenation treatment ADP-induced aggregation significantly decreased in women, spontaneous aggregation in men. How-ever, the nature of the response of platelet functional activity to hyperbaric oxygenation is af-fected by the initial state of the platelet hemostasis. Key words: platelets, hyperbaric oxygenation, platelet aggregation, heart failure, hemo-stasis.

Associative Microgels, New Self Adaptive Systems to Control Fluid Loss in Well Cementing

Fluid loss control additives are critical constituents in a cement slurry formulation to ensure even cement placement and ultimately satisfactory zonal isolation. Many technological options have been developed over the past decades to design fluid loss control additives for cementing. The most popular technologies as of today are either based on water soluble polymers or colloidal particles like latexes. As an alternative approach, in this paper we introduce a new technology based on associative or "sticky" microgels. These microgels are able to associate with one another at elevated concentration but, more surprisingly, are also able to associate under shear in the dilute regime during a filtration process. As a consequence these additives demonstrate outstanding performance as fluid loss control agents. This study focuses first on standard API filtration tests using sticky microgels, and on how their behavior in application differs from traditional systems, in particular water-based soluble polymers such as cellulosic derivatives or synthetic polymers. Our investigations then focus on the working mechanism of the microgel system by analyzing adsorption on the cement surface, rheology, and filter cake structure using Mercury Intrusion Porosimetry (MIP). Finally the behavior of sticky microgels in model filtration tests is explored with either filtration against porous ceramic discs or using microfluidic chips allowing a direct visualization of microgels during filtration. This study demonstrates that associative microgels are not controlling fluid loss through a simple size match between particles and pores within the filter cake but rather through shear-induced aggregation. Microfluidic observations reveal that aggregation occurs irreversibly as microgels are forced through the pores as the filtration process occurs. The shear-induced associated gels are particularly effective at reducing dramatically the filter cake permeability and allowing gas migration control. Interestingly the shear-induced aggregation of associative μgels seems to confer self-adaptive properties of the fluid loss additives with respect to the pore network to be clogged. Indeed, formation of shear aggregated gels larger than the individual microgels can be used to limit fluid loss even if the pore sizes are much larger than the individual microgels.