Determination of fluoroquinolones in bovine milk samples using a pipette‐tip SPE step based on multiwalled carbon nanotubes prior to CE separation

A simple CE–UV method was developed for the simultaneous determination of ciprofloxacin, norfloxacin, and ofloxacin in milk samples. The optimum separation was obtained using a 20 mM ammonium dihydrogenphosphate solution with 2 mM cetyltrimethylammonium bromide at pH 3.0 as the BGE. Satisfactory resolution for structurally very similar analytes, like norfloxacin and ciprofloxacin, was achieved without including any organic solvent. Milk samples were prepared using a simple/extraction procedure based on acidic protein precipitation followed by an SPE step using only 5 mg of multiwalled carbon nanotubes as the sorbent material. The LODs for the three compounds were between 7.5 and 11.6 μg/L and the RSDs for the peak areas were between 2.6 and 4.9%. The complete method was applied to spiked real milk samples with satisfactory recoveries for all analytes (84–106%).     

Synthesis of substituted 5-hydroxypyrazolo[1,5-a]quinoxalin-4-ones

1. Download high-res image (92KB)
2. Download full-size image

     

Validation of ELISA methods for search and quantification of β-n-methylamino-l-alanine in water and fish tissue

Water basins with low hydrodynamic activities can promote the growth and increase in algal biomass due to eutrophication, and toxic cyanobacteria species might then produce metabolites hazardous to human health. Over the last decade, a neurotoxic non-protein amino acid, (2S)-2-amino-3-(methylamino) propanoic acid, known as β-N-methylamino-L-alanine (BMAA), has become of particular interest because it has been hypothesised to be involved in progressive human neurodegenerative pathologies. This toxin can be found both in algal cells and free in water, as well as in some foods of aquatic and terrestrial origin. Analytical methods used for BMAA are often based on chromatography coupled with mass spectrometry, although these techniques involve long and expensive analysis. As the availability of a faster and cheaper screening method would be useful, we tested the only available Enzyme-Linked Immunosorbent Assay kit for BMAA evaluation and validated methods to verify their reliability for the analysis of water and fish muscle. For both matrices, we determined adequate selectivity and repeatability (relative standard deviation < 6%), with recoveries from 70% to 83% at the tested spiking levels; the methods were also robust. These data appear in contrast to a previous evaluation carried out on the same kit in 2013, although this might depend on an improvement to the kit performance. We can conclude that a preliminary determination of BMAA in water, and also in fish tissue after an adequate extraction procedure, can be performed efficiently with the tested kit, which provides for easier monitoring of this dangerous toxin.     

Cellulose derivative/barium titanate composites with high refractive index,conductivity and energy density

Cellulose - This work deals with hydroxypropyl cellulose (HPC)/barium titanate (BT) composites, having small levels of perovskite-like BT loading, i.e. 0.5–2% and being designed for electric...     

The potential of MXene materials as a component in the catalyst layer for the Oxygen Evolution Reaction

MXenes are a class of 2D/layered materials which are highly conductive, hydrophilic, have a large electrochemical surface area and are easily processible into electrodes for energy applications. Since the discovery of MXenes over ten years ago, these materials have been mainly used in the preparation of electrodes for batteries and supercapacitors. However, due to their aforementioned properties, MXenes could potentially be utilised as a component in the catalyst layer for the Oxygen Evolution Reaction (OER). This opinion piece will discuss some of the recent literature in the area of hybrid catalysts consisting of various Transition Metal Oxides (TMOs) and MXenes for the OER. We will also discuss current drawbacks and future outlook in this new area of research.     

Polyextremophilic Chitinolytic Activity by a Marine Strain (IG119) of Clonostachys rosea

The investigation for novel unique extremozymes is a valuable business for which the marine environment has been overlooked. The marine fungus Clonostachys rosea IG119 was tested for growth and chitinolytic enzyme production at different combinations of salinity and pH using response surface methodology. RSM modelling predicted best growth in-between pH 3.0 and 9.0 and at salinity of 0–40‰, and maximum enzyme activity (411.137 IU/L) at pH 6.4 and salinity 0‰; however, quite high production (>390 IU/L) was still predicted at pH 4.5–8.5. The highest growth and activity were obtained, respectively, at pH 4.0 and 8.0, in absence of salt. The crude enzyme was tested at different salinities (0–120‰) and pHs (2.0–13.0). The best activity was achieved at pH 4.0, but it was still high (in-between 3.0 and 12.0) at pH 2.0 and 13.0. Salinity did not affect the activity in all tested conditions. Overall, C. rosea IG119 was able to grow and produce chitinolytic enzymes under polyextremophilic conditions, and its crude enzyme solution showed more evident polyextremophilic features. The promising chitinolytic activity of IG119 and the peculiar characteristics of its chitinolytic enzymes could be suitable for several biotechnological applications (i.e., degradation of salty chitin-rich materials and biocontrol of spoiling organisms, possibly solving some relevant environmental issues).     

Anti-Multiple Myeloma Potential of Secondary Metabolites from Hibiscus sabdariffa—Part 2

Multiple Myeloma (MM) is an aggressive tumor causing millions of deaths every year and currently available therapies are often unsuccessful or correlated with severe side effects. In our previous work we demonstrated that the Hibiscus sabdariffa hydroalcoholic extract inhibits the growth of the MM cell line and we isolated two metabolites responsible for the activity: Hib-ester and Hib-carbaldehyde. Herein we report their interaction with proteasome, one of the main targets in the fight against MM. The molecular modelling study outlined a good interaction of both compounds with the target and these results prompted us to investigate their potential to inhibit proteasome. Metabolites were then isolated from the calyces and an extract with a high content of Hib-ester and Hib-carbaldehyde was prepared. An anticancer profile was drawn, evaluating apoptosis, autophagy and proteasome inhibition, with the anticancer properties being mainly attributed to the Hib-ester and Hib-carbaldehyde, while the proteasome inhibition of the extract could also be ascribed to the presence of anthocyanins, a class of secondary metabolites already known for their proteasome inhibitory activity.     

Diatomaceous Earth for Arthropod Pest Control: Back to the Future

Nowadays, we are tackling various issues related to the overuse of synthetic insecticides. Growing concerns about biodiversity, animal and human welfare, and food security are pushing agriculture toward a more sustainable approach, and research is moving in this direction, looking for environmentally friendly alternatives to be adopted in Integrated Pest Management (IPM) protocols. In this regard, inert dusts, especially diatomaceous earths (DEs), hold a significant promise to prevent and control a wide range of arthropod pests. DEs are a type of naturally occurring soft siliceous sedimentary rock, consisting of the fossilized exoskeleton of unicellular algae, which are called diatoms. Mainly adopted for the control of stored product pests, DEs have found also their use against some household insects living in a dry environment, such as bed bugs, or insects of agricultural interest. In this article, we reported a comprehensive review of the use of DEs against different arthropod pest taxa, such as Acarina, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Ixodida, Lepidoptera, when applied either alone or in combination with other techniques. The mechanisms of action of DEs, their real-world applications, and challenges related to their adoption in IPM programs are critically reported.     

Enriching the Arsenal of Pharmacological Tools against MICAL2

Molecule interacting with CasL 2 (MICAL2), a cytoskeleton dynamics regulator, are strongly expressed in several human cancer types, especially at the invasive front, in metastasizing cancer cells and in the neo-angiogenic vasculature. Although a plethora of data exist and stress a growing relevance of MICAL2 to human cancer, it is worth noting that only one small-molecule inhibitor, named CCG-1423 (1), is known to date. Herein, with the aim to develop novel MICAL2 inhibitors, starting from CCG-1423 (1), a small library of new compounds was synthetized and biologically evaluated on human dermal microvascular endothelial cells (HMEC-1) and on renal cell adenocarcinoma (786-O) cells. Among the novel compounds, 10 and 7 gave interesting results in terms of reduction in cell proliferation and/or motility, whereas no effects were observed in MICAL2-knocked down cells. Aside from the interesting biological activities, this work provides the first structure–activity relationships (SARs) of CCG-1423 (1), thus providing precious information for the discovery of new MICAL2 inhibitors.     

Homogenization of quasi-linear equations with natural growth terms

In this paper we deal with the limit behaviour of the bounded solutions u_ε of quasi-linear equations of the form of Ω with Dirichlet boundary conditions on σΩ. The map a=a(x,ϕ) is periodic in x, monotone in ϕ, and satisfies suitable coerciveness and growth conditions. The function H=H(x,s,ϕ) is assumed to be periodic in x, continuous in [s,ϕ] and to grow at most like |ξ|^p. Under these assumptions on a and H we prove that there exists a function H⁰=H⁰(s,ϕ) with the same behaviour of H, such that, up to a subsequence, (u_ε) converges to a solution u of the homogenized problem -div(b(Du)) + γ|u|^p-2u = H⁰(u,Du) + h(x) on Ω, where b depends only on a and has analogous qualitative properties.