Reporter virus is a versatile tool to visualize and to analyze virus infections. However, for flaviviruses, it is difficult to maintain the inserted reporter genes on the viral genome, limiting its use in several studies that require homogeneous virus particles and several rounds of virus replication. Here, we showed that flanking inserted GFP genes on both sides with ribosome-skipping 2A sequences improved the stability and the consistency of their fluorescent signals for dengue-virus-serotype 2 (DENV2) reporter viruses. The reporter viruses can infect known susceptible mammalian cell lines and primary CD14+ human monocytes. This design can accommodate several fluorescent protein genes, enabling the generation of multi-color DENV2-16681 reporter viruses with comparable replication capabilities, as demonstrated by their abilities to maintain their fluorescent intensities during co-infections and to exclude superinfections regardless of the fluorescent tags. The reported design of multi-color DENV2 should be useful for high-throughput analyses, single-cell analysis, and characterizations of interference and superinfection in animal models.

Vector control, the most efficient tool to reduce mosquito-borne disease transmission, has been compromised by the rise of insecticide resistance. Recent studies suggest the potential of mosquito-associated microbiota as a source for new biocontrol agents or new insecticidal chemotypes. In this study, we identified a strain of Serratia marcescens that has larvicidal activity against Anopheles dirus, an important malaria vector in Southeast Asia. This bacterium secretes heat-labile larvicidal macromolecules when cultured under static condition at 25°C but not 37°C. Two major protein bands of approximately 55 kDa and 110 kDa were present in spent medium cultured at 25°C but not at 37°C. The Liquid Chromatography-Mass Spectrometry (LC-MS) analyses of these two protein bands identified several proteases and chitinases that were previously reported for insecticidal properties against agricultural insect pests. The treatment with protease and chitinase inhibitors led to a reduction in larvicidal activity, confirming that these two groups of enzymes are responsible for the macromolecule's toxicity. Taken together, our results suggest a potential use of these enzymes in the development of larvicidal agents against Anopheles mosquitoes.

A novel tool for the detection of BCR/ABL fusion gene in chronic myelogenous leukemia (CML) was developed by a magneto-polymerase chain reaction (PCR)-enzyme linked gene technique. The forward primers covalently bound to the surface of magnetic nanoparticles allowed a convenient separation of PCR products with high sensitivity (0.5 pg ml(-1)) and high specificity using K562 cell line and CML patients. The results were obtained when the biotinylated-reverse primer bound to streptavidin-horseradish peroxidase (HRP) and hydrolysed the substrate. This novel readout system was approximately 1000-fold more sensitive than the conventional agarose gel electrophoresis. The present technique is practical and useful for following up CML patients and for providing appropriate treatment, particularly to patients in remote areas.

Background Neorautanenia mitis, Hydnora abyssinica, and Senna surattensis are medicinal plants with a variety of traditional uses. In this study, we sought to isolate the bioactive compounds responsible for some of these activities, and to uncover their other potential medicinal properties. Methods The DCM and ethanol extracts of the roots of N. mitis and H. abyssinica, and the leaves of S. surattensis were prepared and their phytochemical components were isolated and purified using chromatographic methods. These extracts and their pure phytochemical components were evaluated in in-vitro models for their inhibitory activities against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Mycobacterium tuberculosis, α-amylase (AA), and α-glucosidase (AG). Results Rautandiol B had significant inhibitory activities against two strains of Plasmodium falciparum showing a high safety ratio (SR) and IC50 values of 0.40 ± 0.07 μM (SR - 108) and 0.74 ± 0.29 μM (SR - 133) against TM4/8.2 and K1CB1, respectively. While (−)-2-isopentenyl-3-hydroxy-8-9-methylenedioxypterocarpan showed the highest inhibitory activity against T. brucei rhodesiense with an IC50 value of 4.87 ± 0.49 μM (SR > 5.83). All crude extracts showed inhibitory activities against AA and AG, with three of the most active phytochemical components; rautandiol A, catechin, and dolineon, having only modest activities against AG with IC50 values of 0.28 mM, 0.36 mM and 0.66 mM, respectively. Conclusion These studies have led to the identification of lead compounds with potential for future drug development, including Rautandiol B, as a potential lead compound against Plasmodium falciparum. The relatively higher inhibitory activities of the crude extracts against AG and AA over their isolated components could be due to the synergistic effects between their phytochemical components. These crude extracts could potentially serve as alternative inhibitors of AG and AA and as therapeutics for diabetes.