Two-in-one sensor of refractive index and Raman scattering using hollow-core microstructured optical waveguides for colloid characterization

Hollow-core microstructured optical waveguides (HC-MOW) have recently emerged in sensing technologies, including the gas and liquid detection for industrial as well as clinical applications. Antiresonant HC-MOW provide capabilities for applications in refractive index (RI) sensing, while the long optical path for analyte-light interaction in HC-MOW leads to increased sensitivity of sensor based on Raman scattering signal measurements. In this study, we developed a two-in-one sensor device using HC-MOW for RI and Raman scattering detection. The performance of the sensor was evaluated by characterizing protein-copolymer multicomponent colloids, specifically, bovine serum albumin (BSA) and poly(N - vinyl-2 -pyrrolidone-co-acrylic acid) P(VP-AA) nano-sized complexes and microbubbles of the corresponding shell. Monocomponent solutions showed linear dependencies of RI and characteristic Raman peak intensities on mass concentration. Multicomponent Raman sensing of BSA@P(VP-AA) complexes and microbubbles revealed that changes in P(VP-AA) characteristic peak intensities can describe interactions between components needed to produce colloid systems. RI sensing of multicomponent colloids demonstrated linear dependence on total mass concentrations for BSA@P(VP-AA) complexes, while corresponding BSA@P(VP-AA) microbubbles can be detected with concentrations as high as 4.0 × 108 MB/mL. Therefore, the developed two-in-one sensor of RI and Raman scattering can be used the robust characterization of albumin-based colloids designed for therapeutic and diagnostic needs.

Modification of bacterial cells for in vivo remotely guided systems

It was shown recently that bacterial strains, which can act specifically against malignant cells, can be used efficiently in cancer therapy. Many appropriate bacterial strains are either pathogenic or invasive and there is a substantial shortage of methods with which to monitor in vivo the distribution of bacteria used in this way. Here, it is proposed to use a Layer-by-Layer (LbL) approach that can encapsulate individual bacterial cells with fluorescently labeled polyelectrolytes (PE)s and magnetite nanoparticles (NP)s. The NP enable remote direction in vivo to the site in question and the labeled shells in the far-red emission spectra allow non-invasive monitoring of the distribution of bacteria in the body. The magnetic entrapment of the modified bacteria causes the local concentration of the bacteria to increase by a factor of at least 5. The PEs create a strong barrier, and it has been shown in vitro experiments that the division time of bacterial cells coated in this way can be regulated, resulting in control of their invasion into tissues. That animals used in the study survived and did not suffer septic shock, which can be attributed to PE capsules that prevent release of endotoxins from bacterial cells.

BACTERIAL CONTAMINATION AND METHODS OF DECONTAMINATION OF BASES COMPLETE REMOVABLE PROSTHESES DURING THE APPLICATION OF ADHESIVE MATERIALS

It turned out that the permanent microbiota of surfaces of acrylic bases of complete removable plastic dentures (CRPD) characterized by several features: the presence of aerobic (7) and anaerobic (10) species. Qualitative and quantitative compositions of microbiocenosis in orthopedic treatment stages have been changed. The revealed patterns require further study in the context of the improvement of decolonization of acrylic bases in the stages of orthopedic treatment by CRPD. Deactivation of acrylic bases of CRPD significantly affects the species composition of microbiota, reduces the quantitative parameters of bacterial contamination. The purpose of our work was determination of bacterial contamination of acrylic bases of CRPD in stages of their clinical exploitation and study of changes in the quantitative composition of the acrylic bases microbiota of CRPD under different decontamination modes. Smears from the inner surface of the acrylic base were stained with Gram and microscopic and seeded on blood agar, Endo agar, Chistovich, Saburo. Species belonging to the micro-organisms were identified by the LAHEMA test system and were determined in colonies forming units (CFUs). These data indicate accumulation under the acrylic base in the course of clinical operation of certain types of microbiota, which requires improvement of the methods of their decontamination. We studied the change in the quantitative and specific composition of the microbiota (bacterial contamination) of acrylic bases CRPD under different modes ("A", "B"). Patients in group "A" used the Sideex solution - a two-component system consisting of a liquid component (glutaraldehyde solution) and a powdery activator, mixed before use to obtain a working activated solution. The liquid component is a clear, colorless solution with a specific odor, which is a 2.2-2.7% aqueous solution of glutaraldehyde, which is an active ingredient, pH=3.0 - 4.5. Powdery activator is a pale-yellow powder containing alkaline components, a corrosion inhibitor, and a dye. The activated working solution is a fluorescent green solution with a specific odor and containing 2.2-2.7% glutaraldehyde; pH=8.2-9.2. (Great Britain). Preparation of the activated solution: a powder-activator is added to the container containing the liquid component (avoiding losses). Cleaning is carried out by the method of full immersion of the prosthesis in solution, with a thickness of the drug over it not less than 1 cm. The dentures are soused in solution for 15 minutes, then thorough washing in the same solution for 1-3 minutes. Sideex activated solution is used for sterilization and disinfection of metal, glass, polymeric (plastic, rubber, etc.) medical products. The dentures of patients from group "B" are decontaminated with 0.2% solution of chlorhexidine bigluconate. The dentures were placed in the solution overnight for 14 days, changing the solution every two days. The decontamination of acrylic bases of CRPD should be considered mode "B" as more effective because of the significant decrease in the species composition of the microbiota (the qualitative indicator of reduction of microbial contamination was 72.0%). It is substantiated that decontamination of acrylic bases of CRPD with mode "A" has a small effect on the species composition of the microbiota, although it significantly (p<0.05) reduces quantitative indicators of microbial contamination. Regarding "B" mode, the species composition of aerobes from 31 lgCFU/ml to 8.7 lgCFU/ml and anaerobes from 42.7 lgCFU/ml to 14.6 lgCFU/ml was considered more effective.

Biodegradable polyelectrolyte/magnetite capsules for MR imaging and magnetic targeting of tumors

Rationale: The tireless research for effective drug delivery approaches is prompted by poor target tissue penetration and limited selectivity against diseased cells. To overcome these issues, various nano- and micro-carriers have been developed so far, but some of them are characterized by slow degradation time, thus hampering repeated drug administrations. The aim of this study was to pursue a selective delivery of magnetic biodegradable polyelectrolyte capsules in a mouse breast cancer model, using an external magnetic field.

Methods: Four different kinds of magnetic polyelectrolyte capsules were fabricated via layer-by-layer assembly of biodegradable polymers on calcium carbonate templates. Magnetite nanoparticles were embedded either into the capsules' shell (sample S) or both into the shell and the inner volume of the capsules (samples C_nS, where n is the number of nanoparticle loading cycles). Samples were first characterized in terms of their relaxometric and photosedimentometric properties. In vitro magnetic resonance imaging (MRI) experiments, carried out on RAW 264.7 cells, allowed the selection of two lead samples that proceeded for the in vivo testing on a mouse breast cancer model. In the set of in vivo experiments, an external magnet was applied for 1 hour following the intravenous injection of the capsules to improve their delivery to tumor, and MRI scans were acquired at different time points post administration.

Results: All samples were considered non-cytotoxic as they provided more than 76% viability of RAW 264.7 cells upon 2 h incubation. Sample S appeared to be the most efficient in terms of T₂-MRI contrast, but the less sensitive to external magnet navigation, since no difference in MRI signal with and without the magnet was observed. On the other side, sample C₆S was efficiently delivered to the tumor tissue, with a three-fold T₂-MRI contrast enhancement upon the external magnet application. The effective magnetic targeting of C₆S capsules was also confirmed by the reduction in T₂-MRI contrast in spleen if compared with the untreated with magnet mice values, and the presence of dense and clustered iron aggregates in tumor histology sections even 48 h after the magnetic targeting.

Conclusion: The highlighted strategy of magnetic biodegradable polyelectrolyte capsules' design allows for the development of an efficient drug delivery system, which through an MRI-guided externally controlled navigation may lead to a significant improvement of the anticancer chemotherapy performance.

Multilocus Genotypes of the Wheat Leaf Rust Fungus Puccinia triticina in Worldwide Regions Indicate Past and Current Long-Distance Migration

Many plant pathogenic fungi have a global distribution across diverse ecological zones and agricultural production systems. Puccinia triticina, the wheat leaf rust fungus, is a major pathogen in many wheat production areas of the world. The objective of this research was to determine the genetic relatedness of P. triticina in different worldwide regions. A total of 831 single-uredinial isolates collected from 11 regions were characterized for multilocus genotype at 23 simple sequence repeat loci and for virulence to 20 lines of wheat with single genes for leaf rust resistance. A total of 424 multilocus genotypes and 497 virulence phenotypes were found. All populations had high heterozygosity and significant correlation between virulence and molecular variation, which indicated clonal reproduction. The populations from North America and South America, Central Asia and Russia, and the Middle East and Europe were closely related for multilocus genotypes and many individual isolates from other continental regions were closely related. Twenty-seven multilocus genotypes were found in more than one continental region, and 13 of these had isolates with identical virulence phenotypes. The wide geographic distribution of identical and highly related multilocus genotypes of P. triticina indicated past and more recent migration events facilitated by the spread of clonally produced urediniospores.

Genetic Analysis of Resistance to Leaf Rust and Yellow Rust in Spring Wheat Cultivar Kenya Kongoni

The Kenyan wheat (Triticum aestivum L.) 'Kenya Kongoni' exhibits high levels of adult plant resistance (APR) to leaf rust (LR) and yellow rust (YR). We determined the genomic regions associated with LR and YR resistance in a population of 148 recombinant inbred lines generated from a cross between 'Avocet-YrA' and Kenya Kongoni. Field experiments to characterize APR to LR and YR were conducted in four and two Mexican or Uruguayan environments, respectively. A linkage map was constructed with 438 diversity arrays technology and 16 simple-sequence repeat markers by JoinMap 4.1 software. Genetic analyses showed that resistance to both rusts was determined by four to five APR genes, including Lr46/Yr29 and Sr2/Lr27/Yr30. Quantitative trait loci (QTL) analysis indicated that pleiotropic APR loci QYLr.cim-1BL corresponding to Lr46/Yr29 and QYLr.cim-7BL that is a putative novel QTL accounted for 5 to 57% and 12 to 35% of the phenotypic variation for resistance to LR and YR, respectively. These loci, in combination with another three LR QTL and two YR QTL, respectively, conferred high levels of resistance to both LR and YR in wheat under Mexican and Uruguayan environments. Among other detected QTL, QLr.cim-1DS, QLr.cim-2BL, and QYLr.icm-7BL may be new loci for APR to both rusts in common wheat.

Function and visual impairment in a population-based study of older adults. The SEE project. Salisbury Eye Evaluation

PURPOSE

The Salisbury Eye Evaluation (SEE) project investigates the impact of vision on functional status in a population-based sample of elderly persons. The prevalence of self-reports of functional status and the association with visual acuity loss are described.

METHODS

A random sample of men and women 65 to 84 years of age from Salisbury, Maryland were recruited for home interviews and clinic examinations. Of the eligible sample, 78% responded to the home questionnaire and 65% responded to the questionnaire and the clinic examination. Binocular visual acuity of each person was measured using ETDRS charts and protocols. Questions were asked concerning activities of daily living, instrumental activities of daily living, physical function, social interaction, and activities of daily vision. Analyses of the association of presenting visual acuity worse than 20/40 with the measures of function were carried out and adjusted for age, race, and sex.

RESULTS

All measures of functional status showed a decline with age; women and blacks were more likely to report difficulties. The age-adjusted proportions of those with visual impairment were not significantly different between men and women (7.2% versus 6.7%; P = 0.60). Black persons had almost twice the rate (10.4%) of white persons (5.6%; P < 0.001). Age, race, gender, and visual impairment were all significantly related to declines in functional status in multivariate models.

CONCLUSIONS

Data on functional status in the project population were similar to national data and confirmed higher rates of disability in women and blacks. Binocular visual acuity worse than 20/40 appeared to have an impact on all the self-report measures of functional status. Further analyses on the interaction of vision with other comorbid conditions on function status clearly are indicated.

In vitro translation of apple chlorotic leaf spot virus (ACLSV) RNA

The genomic RNA of apple chlorotic leaf spot virus was translated in a rabbit reticulocyte lysate system, yielding a large, 190 K product as well as several other polypeptides of smaller size (60, 56, 22 and 15 kDa). The 22 kDa product was immunoprecipitated by an anti-ACLSV serum and comigrated with purified ACLSV coat protein. In vitro translation of RNA transcripts prepared from cloned ACLSV cDNAs demonstrates that the coat protein is synthesised by initiation on the second in frame AUG codon of the 28 kDa open reading frame located at the 3' end of the genome. In the in vitro translation system used, the ability of various ACLSV-derived RNAs to direct the synthesis of the coat protein appears to be the result of initiation on the internal AUG codon.

The hrp gene locus of Pseudomonas solanacearum, which controls the production of a type III secretion system, encodes eight proteins related to components of the bacterial flagellar biogenesis complex

Five transcription units of the Pseudomonas solanacearum hrp gene cluster are required for the secretion of the HR-inducing PopA1 protein. The nucleotide sequences of two of these, units 1 and 3, have been reported. Here, we present the nucleotide sequence of the three other transcription units, units 2, 4 and 7, which are together predicted to code for 15 hrp genes. This brings the total number of Hrp proteins encoded by these five transcription units to 20, including HrpB, the positive regulatory protein, and HpaP, which is apparently not required for plant interactions. Among the 18 other proteins, eight belong to protein families regrouping proteins involved in type III secretion pathways in animal and plant bacterial pathogens and in flagellum biogenesis, while two are related solely to proteins involved in secretion systems. For the various proteins found to be related to P. solanacearum Hrp proteins, those in plant-pathogenic bacteria include proteins encoded by hrp genes. For Hrp-related proteins of animal pathogens, those encoded by the spa and mxi genes of Shigella flexneri and of Salmonella typhimurium and by the ysc genes of Yersinia are involved in type III secretion pathways. Proteins involved in flagellum biogenesis, which are related to Hrp proteins of P. solancearum, include proteins encoded by fli and flh genes of S. typhimurium, Bacillus subtilis and Escherichia coli and by mop genes of Erwinia carotovora. P. solanacearum Hrp proteins were also found to be related to proteins of Rhizobium fredii involved in nodulation specificity.

Analysis of the dsRNAs of apple chlorotic leaf spot virus

Double-stranded RNAs were isolated from plants infected with five different isolates of apple chlorotic leaf spot virus (ACLSV). Analysis by PAGE and by Northern blot hybridization showed that six major species of viral dsRNA of approximately 7.5, 6.4, 5.4, 2.2, 1.1 and 1.0 kbp can be detected in infected plants, irrespective of the ACLSV isolate used. In addition to the dsRNA of 7.5 kbp corresponding to the full-length genome, the size and position on the genome of the 2.2 and 1.1 kbp species indicate that these are very probably double-stranded forms of subgenomic RNAs allowing the expression of the internal open reading frames coding respectively for the ACLSV 50K and coat proteins. The subgenomic messenger for the coat protein was indeed detected in total RNA preparations from infected plants. Surprisingly, the two most abundant dsRNA species, of 6.4 and 5.4 kbp, were found to be 5'-coterminal with the genomic RNA. A model for the expression of the genome of ACLSV and for the production of the molecules 5'-coterminal with the genomic RNA is presented.

Nucleotide sequence and genomic organization of apple chlorotic leaf spot closterovirus

The nucleotide sequence of Apple chlorotic leaf spot closterovirus (ACLSV) genomic RNA has been determined from cDNA clones. It is 7555 nucleotides in length excluding the 3' terminal poly(A) tail and contains three putative open reading frames capable of encoding proteins of 216.5, 50, and 28 kDa. ACLSV RNA has untranslated regions of 151 and 190 nucleotides at its 5' and 3' termini, respectively. The 216.5-kDa ORF encodes a protein which contains the conserved "signature" sequences and has significant homology with the proteins suspected to be involved in viral RNA replication of members of the "Sindbis-like" supergroup of viruses. On the basis of distant homologies with viral movement proteins (M proteins), the 50-kDa ORF is suspected to encode a protein responsible for virus cell-to-cell spread. The 28-kDa ORF contains, in frame, a smaller 21.5-kDa ORF encoding the coat protein of ACLSV. These results show that ACLSV and probably at least the subgroup A of closteroviruses should be regarded as members of the "Sindbis-like" supergroup of RNA viruses.