Microdroplet-based multiplex PCR on chip to detect foodborne bacteria producing biogenic amines

The development of fast, reliable and culture-independent molecular tools to detect bacteria producing biogenic amines deserves the attention of research and ultimately of the food industry in order to protect consumers' health. Here we present the application of a simple, low-cost, fast and sensitive method to perform microdroplet-based multiplex PCR, directly on a food matrix, for the simultaneous detection of bacterial genes involved in biogenic amine biosynthesis. After inoculating wine with Lactobacillus brevis IOEB 9809, cell lysis and DNA amplification are performed in one single step, without preliminary nucleic acid extraction or purification treatments. The assay is performed in about 30 min, requiring 150 nL of starting sample and it enables the detection of down to 15 bacterial cells. With respect to traditional culture techniques, the speed, the simplicity and the cheapness of this procedure allow an effective monitoring of microbial cells during food-making and processing.     

Cloning and characterization of a β-N-acetylglucosaminidase (BmFDL) from silkworm Bombyx mori

In insects, β-N-acetylglucosaminidase (GlcNAcase) participates in critical physiological processes such as fertilization, metamorphosis, and glycoconjugate degradation. Insects produce glycoproteins carrying paucimannosidic-type N-glycans, the terminal GlcNAc residue of which is cleaved by a GlcNAc-linkage specific GlcNAcase, also known as the fused lobes (FDL) protein. To obtain information on the structure of GlcNAcases and insight into their contribution to physiological processes, we cloned Bombyx mori FDL (BmFDL) from silkworm larvae. The full-length cDNA (1.9 kb) encoded a protein of 633 amino acids with 42% amino acid sequence identity to Drosophila melanogaster FDL (DmFDL). Recombinant BmFDL cleaved only β-1,2-linked GlcNAc residues from the α-1,3 branch of biantennary N-glycan. This substrate specificity was similar to that of DmFDL. Microsomal FDL activity was inhibited by anti-BmFDL antibodies. Taken together, our results suggest that BmFDL is a N-glycan-processing GlcNAcase in B. mori.     

Single muscle fiber analysis of myoclonus epilepsy with ragged-red fibers

We examined two muscle biopsy specimens from a proband and her mother with myoclonus epilepsy with ragged-red fibers (MERRF), both obtained at an interval of about 10 years, using histochemistry, in situ hybridization, and single-fiber polymerase chain reaction. Total (wild-type and mutant) mitochondrial DNAs (mtDNAs) were greatly increased in ragged-red fibers (RRF) over non-RRF in all muscle specimens analyzed. The proportion of mutant mtDNA was also significantly higher in RRF than in non-RRF. By comparing the first and second muscle biopsied specimens in each patient, we found that while the proportion of RRF, cytochrome coxidase deficient fibers, and mutant DNA in muscle changed over a 10-year period, the proportion of wild-type and mutant mtDNAs in RRF and in non-RRF was similar between the two specimens. These results suggest that the ratio of wild-type to mutant mtDNAs in RRF and non-RRF in MERRF is at a steady state level in each muscle fiber, without replicative advantage of mutant mtDNA.     

Copolymerization of unsaturated polyester with styrene in inverted emulsion

Copolymerization of unsaturated polyester with styrene in water-in-oil (W/O) type emulsion was carried out with the use of various basic compounds as emulsifiers. It was found that a stable, gellike W/O type emulsion of unsaturated polyester resin is formed only when pK_a's of the bases are above 6 and their concentrations are higher than some critical value. In these conditions, water can be dispersed in emulsion up to 900% to the resin. By polymerization, the stable W/O type emulsion is transformed to a white solid copolymer which is dry to the touch and which contains 90–95% of initially added water. It was confirmed that the basic compounds react with the carboxylic group of the polyester to form at the water-resin interface polyester salts, which act as true emulsifying agents. The stabilization mechanism of the emulsion at various concentrations of the polyester salt was investigated, mainly by microscopic observations, and an interpretation of the critical value of emulsifier concentration is proposed.     

Propagation Delay of an RC-Chain With a Ramp Input

In this brief, two simple semi-analytical models which allow the estimation of the propagation delay of an RC-chain with a linear input are presented. The closed-form models can be used to evaluate the propagation delay of wires in modern VLSI and ULSI processes. The two approximations, a continuous function and a piecewise function, exhibit a maximum error lower than 15% at the end of the chain. The models have been validated extensively through circuit simulations. In particular, 1000 different RC-chains have been considered and simulated demonstrating the accuracy of the proposed models with respect to the most widely used Elmore delay metric     

New Class of High-<Emphasis Type="Italic">T</Emphasis><Subscript>C</Subscript> Diluted Ferromagnetic Semiconductors Based on CaO without Transition Metal Elements

We propose new-type ferromagnetic semiconductors based on CaO and K₂S without any transition metal elements. These materials show transparent and half-metallic ferromagnetism if the deep-impurity-band width (W) induced by doping of C, N, Si, or Ge impurities, and the electron-correlation energy (U) satisfy the Stoner’s condition of highly correlated electron system (U>W). Based on our first-principles calculations, we demonstrate that these materials satisfy the Stoner’s condition, and could be new candidates for transparent and half-metallic DMSs.     

Urinary leukotriene E4 and 11-dehydrothromboxane B2 in patients with aspirin-sensitive asthma

The objective of this study was to define the participation of cysteinyl leukotrienes (LTs) or thromboxane A2 in the pathogenesis of aspirin-sensitive asthma (ASA). Leukotriene E4 (LTE4) and 11-dehydrothromboxane B2 (11DTXB2) values in spot urine were measured in 22 asthmatics with a history of aspirin sensitivity and in 17 without such a history (non-aspirin-sensitive asthma [NASA]) in the outpatient clinic. The urinary LTE4 value was significantly higher in ASA patients than in NASA (340 +/- 47 vs 65 +/- 15 pg/mg.cr, P < 0.001), but there was no significant difference in urinary 11DTXB2 between the two groups (891 +/- 77 vs 657 +/- 90 pg/mg.cr). A high value of LTE4 was not associated with type of asthma, severity of disease, oral prednisolone treatment, sex, or age. A higher value of 11DTXB2 was observed in the atopic type than the nonatopic type in ASA (1086 +/- 111 vs 697 +/- 147 pg/mg.cr, P < 0.05). No correlation was observed between urinary LTE4 and 11DTXB2 in either ASA or NASA. In conclusion, LTs may play an important role in the pathogenesis of ASA, and TXA2 in the pathogenesis of the atopic type in ASA.