An Effective Method to Purify Plasmodium falciparum DNA Directly from Clinical Blood Samples for Whole Genome High-Throughput Sequencing

Highly parallel sequencing technologies permit cost-effective whole genome sequencing of hundreds of Plasmodium parasites. The ability to sequence clinical Plasmodium samples, extracted directly from patient blood without a culture step, presents a unique opportunity to sample the diversity of “natural” parasite populations in high resolution clinical and epidemiological studies. A major challenge to sequencing clinical Plasmodium samples is the abundance of human DNA, which may substantially reduce the yield of Plasmodium sequence. We tested a range of human white blood cell (WBC) depletion methods on P. falciparum-infected patient samples in search of a method displaying an optimal balance of WBC-removal efficacy, cost, simplicity, and applicability to low resource settings. In the first of a two-part study, combinations of three different WBC depletion methods were tested on 43 patient blood samples in Mali. A two-step combination of Lymphoprep plus Plasmodipur best fitted our requirements, although moderate variability was observed in human DNA quantity. This approach was further assessed in a larger sample of 76 patients from Burkina Faso. WBC-removal efficacy remained high (<30% human DNA in >70% samples) and lower variation was observed in human DNA quantities. In order to assess the Plasmodium sequence yield at different human DNA proportions, 59 samples with up to 60% human DNA contamination were sequenced on the Illumina Genome Analyzer platform. An average ∼40-fold coverage of the genome was observed per lane for samples with ≤30% human DNA. Even in low resource settings, using a simple two-step combination of Lymphoprep plus Plasmodipur, over 70% of clinical sample preparations should exhibit sufficiently low human DNA quantities to enable ∼40-fold sequence coverage of the P. falciparum genome using a single lane on the Illumina Genome Analyzer platform. This approach should greatly facilitate large-scale clinical and epidemiologic studies of P. falciparum

Delineation of Stage Specific Expression of Plasmodium falciparum EBA-175 by Biologically Functional Region II Monoclonal Antibodies

EBA-175 binds its receptor sialic acids on glycophorin A when invading erythrocytes. The receptor-binding region (RII) contains two cysteine-rich domains with similar cysteine motifs (F1 and F2). Functional relationships between F1 and F2 domains and characterization of EBA-175 were studied using specific monoclonal antibodies (mAbs) against these domains..The role of the F1 and F2 domains in erythrocyte invasion and binding was elucidated with mAbs. These mAbs interfere with native EBA-175 binding to erythrocyte in a synergistic fashion. The stage specific expression of EBA-175 showed that the primary focus of activity was the merozoite stage. A recombinant RII protein vaccine consisting of both F1 and F2 domains that could induce synergistic activity should be optimal for induction of antibody responses that interfere with merozoite invasion of erythrocytes

Use of a spectrophotometer for colour measurements and classification of cotton

W artykule przedstawiono badania nad możliwością wykorzystania spektrofotometru w pomiarach koloru i klasyfikacji bawełny. Dotychczas kolor bawełny jest oceniany za pomocą linii HVI (High Volume Instrument). Współrzędne barwy: współczynnik odbicia światła (Rd) i stopień zażółcenia (+b) wg HVI są specyficzne dla bawełny, natomiast nie stosuje się ich do oceny barwy innych materiałów. Tymczasem na całym świecie w pomiarach barwy stosowane są składowe barwy w trójwymiarowej przestrzeni barwowej CIELab. Przeprowadzone badania pozwoliły na wyznaczenie równań regresji, które umożliwiają obliczanie wskaźników (Rd) i (+b) w oparciu o wartości współrzędnych barwy L* i b* otrzymywane za pomocą spektrofotometru.The colour grade of cotton is determined by a degree of the reflectance (Rd) and yellowness (+b). These parameters are instrumentally measured by the HVI. Both (Rd) and (+b) are specific for cotton, whereas all over the world colour assessment is performed in the globally recognized CIE L*a*b* colour system. The aim of this work was to analyse application of a spectrophotometer for cotton colour assessment and colour grading. 48 cotton samples of different origin were measured in the range of their colour parameters by means of both HVI and spectrophotometer Datacolor 650. Regression analysis carried out on a basis of the experimental data allowed determining equations which enabled calculation of (Rd) and (+b) parameters on a basis of the L* and b* results obtained from the spectrophotometer. Experimental verification based on 34 cotton samples different than those used for the model building confirmed the good quality of predicting the values of the (Rd) and (+b) parameters by means of the elaborated regression equations

Permeability properties of single jersey fabrics made of hollow yarns

In this work effect of using hollow yarns on the permeability properties of the single jersey knitted fabrics were studied. Firstly yarns were produced by ring spinning machine using cotton, viscose and acrylic fibres in the mantle and water soluble polyvinyl alcohol (PVA) fibre in the core. Single jersey fabrics were knitted and PVA core was removed subsequently by washing process to create hollow yarn. Weight, air permeability and water transmission rate properties of fabrics were measured before and after washing and compared with reference fabrics. Due to the removal of PVA fibres from the yarn core after washing treatment, air permeability and water vapour transmission rate of the all kind of single jersey fabrics which were produced with hollow yarns increased as well as weight of the fabrics decreased which will cause more comfort during any exercise. It was also found that mantle fibre type and PVA ratio have significant effect on the fabric properties. © 2017 The Textile Institute