Biochemical aspects of flight and flightlessness in Gryllus: flight fuels,enzyme activities and electrophoretic profiles of flight muscles from flight-capable and flightless morphs

Female Gryllus assimilis subjected to 4.5-7.7h continuous tethered flight had significantly lower amounts of total lipid, triglyceride and total soluble carbohydrate compared with unflown controls. A much greater amount of total lipid (6.3mg) was used during flight compared with carbohydrate (0.14mg). Flown individuals also had substantially reduced amounts of injected, radiolabeled [(14)C]-oleic acid. Activities of lipid, carbohydrate and amino acid catabolizing enzymes in flight muscles of G. assimilis and its wing-polymorphic congener, G. firmus, were very similar to activities in insects which primarily utilize lipid to power flight. By contrast, enzyme activities were very different from those in insects which primarily or exclusively use carbohydrate or proline as a flight fuel. These results strongly implicate lipid as the major flight fuel in Gryllus. Previous studies have shown that lipid levels are higher in flight-capable (long-winged) G. firmus that have small ovaries compared with flightless (short-winged) females that have large ovaries. Results of the present and previous studies collectively indicate that elevated lipid in long-winged G. firmus represents an energetic cost of flight capability which reduces (trade-offs with) reproduction in Gryllus. In G. firmus, mass-specific activities of nearly all enzymes were considerably reduced in underdeveloped, and to a lesser degree in histolyzed muscle, compared with fully-developed flight muscle. An important exception was alanine aminotransferase, whose activity was the highest in histolyzed muscle, and which may be involved in the catabolism of amino acids derived from muscle degradation. Despite the dramatic differences in enzyme activity, electrophoretic profiles of soluble flight-muscle proteins differed only subtly between fully-developed and underdeveloped or histolyzed flight muscles.     

Fully automated point-of-care differential diagnosis of acute febrile illness

BackgroundIn this work, a platform was developed and tested to allow to detect a variety of candidate viral, bacterial and parasitic pathogens, for acute fever of unknown origin. The platform is based on a centrifugal microfluidic cartridge, the LabDisk (“FeverDisk” for the specific application), which integrates all necessary reagents for sample-to-answer analysis and is processed by a compact, point-of-care compatible device.Methodology/Principal findingsA sample volume of 200 μL per FeverDisk was used. In situ extraction with pre-stored reagents was achieved by bind-wash-elute chemistry and magnetic particles. Enzymes for the loop-mediated isothermal amplification (LAMP) were pre-stored in lyopellet form providing stability and independence from the cold chain. The total time to result from sample inlet to read out was 2 h. The proof-of-principle was demonstrated in three small-scale feasibility studies: in Dakar, Senegal and Khartoum, Sudan we tested biobanked samples using 29 and 9 disks, respectively; in Reinfeld, Germany we tested spiked samples and analyzed the limit of detection using three bacteria simultaneously spiked in whole blood using 15 disks. Overall during the three studies, the FeverDisk detected dengue virus (different serotypes), chikungunya virus, Plasmodium falciparum, Salmonella enterica Typhi, Salmonella enterica Paratyphi A and Streptococcus pneumoniae.Conclusions/SignificanceThe FeverDisk proved to be universally applicable as it successfully detected all different types of pathogens as single or co-infections, while it also managed to define the serotype of un-serotyped dengue samples. Thirty-eight FeverDisks at the two African sites provided 59 assay results, out of which 51 (86.4%) were confirmed with reference assay results. The results provide a promising outlook for future implementation of the platform in larger prospective clinical studies for defining its clinical sensitivity and specificity. The technology aims to provide multi-target diagnosis of the origins of fever, which will help fight lethal diseases and the incessant rise of antimicrobial resistance.     

A novel fluorescent sensor based on electrosynthesized benzene sulfonic acid‐doped polypyrrole for determination of Pb(II) and Cu(II)

To develop conducting organic polymers (COPs) as luminescent sensors for determination of toxic heavy metals, a new benzene sulfonic acid‐doped polypyrrole (PPy‐BSA) thin film was electrochemically prepared by cyclic voltammetry (CV) on flexible indium tin oxide (ITO) electrode in aqueous solution. PPy‐BSA film was characterized by FTIR spectrometry, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The optical properties of PPy‐BSA were investigated by ultraviolet (UV)‐visible absorption and fluorescence spectrometry in dimethylsulfoxide (DMSO) diluted solutions. PPy‐BSA fluorescence spectra were strongly quenched upon increasing copper(II) ion (Cu²⁺) and lead(II) ion (Pb²⁺) concentrations in aqueous medium, and linear Stern–Volmer relationships were obtained, which indicated the existence of a main dynamic fluorescence quenching mechanism. BSA‐PPy sensor showed a high sensitivity for detection of both metallic ions, Cu²⁺ and Pb²⁺, with very low limit of detection values of 3.1 and 18.0 nM, respectively. The proposed quenching‐fluorimetric sensor might be applied to the determination of traces of toxic heavy metallic ions in water samples.     

The Robustness of Recombination Frequency Estimates in Intercrosses with Dominant Markers

The robustness of the maximum likelihood estimates of recombination frequencies has been investigated in double intercrosses with complete dominance at both loci. The robustness was investigated with respect to bias in the recombination frequency estimates due to: (1) limited sample sizes, (2) heterogeneity in recombination frequencies between sexes or among meioses and (3) factors that distort the segregation-misclassification or differential viability. In the coupling phase, the recombination frequency estimates are quite robust with respect to most of the investigated factors. Potentially, the most serious cause of a bias is misclassifications, which tend to increase the recombination frequency estimates. In the repulsion phase, misclassifications are particularly serious, leading to extreme discrepancies between true and observed values. In addition, limited sample size and sex differences in recombination can also bias recombination frequency estimates in repulsion. These effects may pose serious problem in genetic mapping with random amplified polymorphic DNA (RAPD) markers.     

Interface between haustoria of parasitic members of the Scrophulariaceae and their hosts: A histochemical and immunocytochemical approach

Summary The haustorial structure of three African parasitic members of the family Scrophulariaceae (Buchnera hispida, Rhamphicarpa fistulosa, andStriga hermonthica) has been studied with regard to the interface between haustoria and the invaded host roots. Immunocytochemical observations at the light and electron microscopical level were carried out with monoclonal antibodies against pectin. JIM5, JIM7, and hydroxyproline-rich glycoprotein (HRGP), LM1. Lignins have been visualized by phloroglucinolhydrochloric acid staining. At the margin of the lateral interface (contact area of host root cortex and parasite cells), JIM5- and JIM7-labelled substances accumulate between parasite papillae and the host root surface indicating that pectins are implicated in sealing the parasite to the attacked host organ. The lateral interface is characterized by the presence of compressed, necrotic host cells, whereas the central interface (contact area between host stele and parasite cells) is generally devoid of host cell remnants. Phenolic substances and/or lignins can be found at the site of penetration of the haustorium into the host root. These observations and the fact that HRGPs accumulate at the host side of the interface support the view of, at least, a partial defense reaction in the invaded host root tissues. Within haustoria, HRGPs were restricted to differentiating xylem elements, implying a spatio-temporal regulation of HRGPs in developmental processes.Abbreviations BSA bovine serum albumin - FITC fluorescein isothiocyanate - HRGP hydroxyproline-rich glycoprotein - LM light microscopy - MAb monoclonal antibody - TBSB Tris-buffered saline with bovine serum albumin - TBSB-T Tris-buffered saline with bovine serum albumin and Tween 20 - TEM transmission electron microscopy