Antisense oligodeoxynucleotides: useful tool for search and assessment of new targets for anti-malarial drugs.

We investigated about targeting for new antimalarial drugs using antisense (AS) oligodeoxynucleotides (ODNs). Synthetic nuclease-resistant ODNs (phosphorothioate (PS) ODNs and ODNs containing 4'alpha-C-(2-aminoethyl)thymidines (4'-amino ODNs)) which target mitochondrial succinate dehydrogenase (SDH) iron-sulfur subunit (IP), had antimalarial activity (EC50; about 1.0 microM). Furthermore we showed that intra-parasitic SDH IP mRNA levels, which were detected using quantitative RT-PCR assay, were decreased 13% of control after the 24 h expose to SDH IP AS. From the results, we conclude that SDH has potential as the target for novel antimalarials, and AS ODNs is effective for search and assessment of targets for new antimalarial drugs.     

Species-identification dots: a potent tool for developing genome microbiology

Identification of species has long been done by phenotype-based methodologies. Recently, genotype-based species identification has been shown to be possible by way of Genome profiling, which is based on a temperature gradient gel electrophoresis (TGGE) analysis of random PCR products. However, the results, though sufficient in information, provided by genome profiling were complicated and difficult to deal with objectively. To cope with this, a technology of utilizing species identification dots (spiddos), which corresponds to structural transition points of DNAs, was introduced. Pattern similarity score (PaSS), derived from spiddos, was shown to be usable for quantitatively measuring the closeness between genomes. This was demonstrated with the experiments applied to the genomes of Escherichia coli O157:H7 (19 strains). The same genomes were also examined by sequencing and RFLP methods in order to compare the effectiveness of these three methods. As a result, the spiddos method was shown to give reasonable results and to be the most advantageous for measuring the closeness between species in general. This means that spiddos is pushing the heavy gate open for genome microbiology.     

IR spectroscopy as a new tool for evidencing antitumor drug signatures

There is a growing interest for screening antitumor drugs for their mechanism of action on cancer cells. Yet, screening for “modes of action” presents a technical challenge that is beyond the capability of conventional methods used in cellular or molecular biology. Several studies have highlighted the advantages of using infrared spectroscopy for diagnostic purposes at the clinical level for identifying cell types. In the present work, we suggest that the Fourier Transform Infrared (FTIR) spectrum of cells exposed to anti-cancer drugs could offer a unique opportunity to obtain a fingerprint of all molecules present in the cells and to observe, with a high sensitivity, the metabolic changes induced by potential anti-cancer drugs. Ouabain is one of the most potent cardenolides, which acts by inhibiting sodium pump activity. Cardenolides represent a class of compounds that are intended to soon enter clinical trials in oncology. In order to evaluate the potential of infrared spectroscopy to yield a signature for ouabain action on cancer cells, human prostate cancer PC-3 cells were treated with 36 nM ouabain, a sub-lethal concentration. Using ouabain as a model, we have thus demonstrated the possibility of using IR spectroscopy in the assessment of the global effects of an investigational compound on the cell constituents, thus contributing to setting up a new method for screening for novel anti-cancer agents in general, and potential anti-cancer cardenolides in particular. The most spectacular data obtained strongly suggest a modification in the nature of the cell lipids.     

Quantum dots and peptides: a bright future together

Nanocrystalline semi-conductor materials, called quantum dots (QDs), exhibit unique optical and spectroscopic properties, which include, broad absorption, narrow and tunable emission, resistance to photobleaching, strong luminescence, and long luminescent lifetimes. These remarkable properties of QDs have resulted in their use as an alternative to both small-molecule and protein fluorophores in innumerable biological applications. The overlap of QDs with the rich chemistry and biology that is characteristic of the peptide arena is an emerging research area. Peptides engineered with appropriate cysteines or histidines have served as ligands for producing water soluble QDs as well as for tagging protein ligands and biosensors to QD surfaces. Incorporation of cell-penetrating peptides on QD surfaces has allowed for the translocation of functionalized QDs into cells for intracellular imaging applications. QDs containing fluorescently labeled peptide substrates have shown utility in the development of novel protease assays. Moreover, QDs-labeled peptides that serve as ligands for cellular receptors provide an alternative to antibody mediated imaging at the whole-cell and single molecule level to study receptor distribution and trafficking. This review highlights the overlap between QD and peptide chemistry and speculates on future research directions.     

Microbial biotransformation: a tool for drug designing

For centuries microbial biotransformation has proved to be an imperative tool in alleviating the production of various chemicals used in food, pharmaceutical, agrochemical and other industries. In the field of pharmaceutical research and development, biotransformation studies have been extensively applied to investigate the metabolism of compounds (leads, lead candidates, etc.) using animal models. The microbial biotransformation phenomenon is then commonly employed in comparing metabolic pathways of drugs and scaling up the metabolites of interest discovered in these animal models for further pharmacological and toxicological evaluation. Microorganisms can conveniently afford drugs difficult obtained via synthesis. The plethora of reported microbial biotransformations along with its added benefits has already invoked further research in bioconversion of novel and structurally complex drugs. This review alternatively discusses the prospect of microbial biotransformation studies as a significant element ameliorating drug discovery and design in terms of cost-effectiveness, environment protection and greater structural diversity as compared to animal models used to study metabolism. To explicate the microbial biotransformation paradigm in drug designing 3 main areas in this aspect have been analyzed: 1—lead expansion: obtaining pharmacologically improved metabolites from bioactive molecules; 2—biosynthesis of precursors/intermediates involved in the production of bioactive molecules; 3—resolution of racemic mixture to obtain enantiomers possessing different pharmacological profiles.     

Clinical manifestations of new versus recrudescent malaria infections following anti-malarial drug treatment

ABSTRACT: BACKGROUND: Distinguishing new from recrudescent infections in post-treatment episodes of malaria is standard in anti-malarial drug efficacy trials. New infections are not considered malaria treatment failures and as a result, the prevention of subsequent episodes of malaria infection is not reported as a study outcome. However, in moderate and high transmission settings, new infections are common and the ability of a short-acting medication to cure an initial infection may be outweighed by its inability to prevent the next imminent infection. The clinical benefit of preventing new infections has never been compared to that of curing the initial infection. METHODS: Children enrolled in a sulphadoxine-pyrimethamine efficacy study in Blantyre, Malawi from 1998-2004 were prospectively evaluated. Six neutral microsatellites were used to classify new and recrudescent infections in children aged less than 10 years with recurrent malaria infections. Children from the study who did not experience recurrent parasitaemia comprised the baseline group. The odds of fever and anaemia, the rate of haemoglobin recovery and time to recurrence were compared among the groups. RESULTS: Fever and anemia were more common among children with parasitaemia compared to those who remained infection-free throughout the study period. When comparing recrudescent vs. new infections, the incidence of fever was not statistically different. However, children with recrudescent infections had a less robust haematological recovery and also experienced recurrence sooner than those whose infection was classified as new. CONCLUSIONS: The results of this study confirm the paramount importance of providing curative treatment for all malaria infections. Although new and recrudescent infections caused febrile illnesses at a similar rate, recurrence due to recrudescent infection did have a worsened haemological outcome than recurrence due to new infections. Local decision-makers should take into account the results of genotyping to distinguish new from recrudescent infections when determining treatment policy on a population level. It is appropriate to weigh recrudescent malaria more heavily than new infection in assessing treatment efficacy.     

Functional assays as prismatic views of drug activity: relevance to new drug discovery

The two main processes involved in new drug discovery are screening and lead optimization; the latter process encompasses the dialogue between pharmacologists and medicinal chemists with the aim of maximizing primary activity and druglike properties of compounds. The pharmacological assay is the main tool in both of these processes; this will be discussed with special attention to new information regarding the signaling and networking of seven transmembrane receptors. In particular, the assays used for lead optimization will be discussed in terms of detecting and developing drugs that specifically emphasize some signaling pathways and not others, all through the stabilization of unique receptor protein conformations. There is considerable data to indicate that these are real phenomena that may be exploited for therapeutic advantage. A therapeutically relevant example will be discussed from a recent program designed to block entry of HIV-1 for the prevention and therapy of AIDS. The allosteric modulator aplaviroc (873140) and other allosteric modulators will be highlighted with reference to the development of future drugs that block the involvement of receptors in pathological process but otherwise allow them to function normally. In AIDS, this would allow the natural chemokine systems to assist in the protection against further HIV-1 infection.     

Split-seed: a new tool for maize researchers

Until recently, immature embryos have been a choice tissue for manipulation in culture for regeneration and production of transgenic maize plants. The utility of this explant has been compromised by low output, genotype dependence and time-consuming incubation in tissue culture. We have developed a new explant, the split-seed, which addresses these limitations by formally treating each seed as though it were a “dicot”. By splitting maize seed longitudinally, three different tissues: the scutellum, the coleoptilar-ring and the shoot apical meristems are simultaneously exposed. The cells of these tissues can be made competent to enhance the regeneration, given that the molecular networks resulting from exposure of the split-seed to hormones is likely to be different from whole seed and, in turn, affects the in vitro response. Using this explant, callus induction frequency exceeded 92% and the regeneration frequency was 76%. The mean number of shoots regenerated via callus was 11 shoots per callus clump and 28 shoots per explant at first sub-culture. All of the regenerated plants survived and were 95% fertile. The large numbers of fertile plants produced were regenerated in 6–8 weeks. Finally, the incidence of regenerated plants varies as a function of growth regulator profile.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Bacterial motility as a potential tool for rapid toxicity assays

Summary Bacterial motility was evaluated as a potential tool for the rapid assay of the toxicity of chemicals to microorganisms. The level of toxicity was evaluated by the chemical concentration which caused a 50% reduction in motile bacteria at the 60 s of exposure to toxicants. Assay results showed a good correlation with those obtained from a conventional growth inhibition test.     

Neoglycoenzymes: a versatile tool for lectin detection in solid-phase assays and glycohistochemistry

Carbodiimide-mediated coupling of p-aminophenyl glycosides to a naturally nonglycosylated enzyme yields a neoglycoenzyme. This compound combines inherent enzymatic activity with synthetically conferred ligand properties to lectins. Appropriate choice of the ligand allows custom-made synthesis to reliably detect various types of lectins. To exemplify practical applications of this class of compounds, glycosylated bacterial beta-galactosidase has been employed to quantitate plant lectins, immobilized on plastic surfaces as well as on nitrocellulose. Competitive inhibition by specific sugar ascertained the dependence of binding on protein--carbohydrate interactions. In view of lectins as tools, a sandwich lectin-binding assay for high mannose-type glycoprotein detection has been modified to principally facilitate wide application to other lectin-reactive sugar chains by introducing the neoglycoenzyme. In addition to lectin determination in solid-phase assays, neoglycoenzymes allow one to glycohistochemically localize endogenous lectins in tissue prints and tissue sections with a minimum number of steps. This nonradioactive, rapid, sensitive, and convenient assay concept, based on conjugation of a ligand to an enzyme with maintenance of its receptor-binding activity, may find extended application beyond lectinology in receptor analysis.     

methGraph: A genome visualization tool for PCR-based methylation assays

Abnormalities in DNA methylation of CpG islands that play a role in gene regulation affect gene expression and hence play a role in disease, including cancer. Bisulfite-based DNA methylation analysis methods such as methylation-specific PCR (MSP) and bisulfite sequencing (BiSeq) are most commonly used to study gene-specific DNA methylation. Assessing specificity and visualizing the position of PCR primers in their genomic context is a laborious and tedious task, primarily due to the sequence changes induced during the bisulfite conversion. For this purpose, we developed methGraph, a web application for easy, fast and flexible visualization and accurate in silico quality evaluation of PCR-based methylation assays. The visualization process starts by submitting PCR primer sequences for specificity assessment and mapping on the genome using the BiSearch ePCR primer-search algorithm. The next step comprises the selection of relevant UCSC genome annotation tracks for display in the final graph. A custom track showing all individual CpG dinucleotides, representing their distribution in the CpG island is also provided. Finally, methGraph creates a BED file that is automatically uploaded to the UCSC genome browser, after which the resulting image files are extracted and made available for visualization and download. The generated high-quality figures can easily be customized and exported for use in publications or presentations. methGraph is available at http://mellfire.ugent.be/methgraph/.     

Panalysis: a new spreadsheet-based tool for pandemic planning

Publicly available influenza modeling tools are of limited use to hospitals and local communities in planning for a severe pandemic. We developed Panalysis, a new tool to estimate the likely healthcare consequences of a pandemic and to aid hospitals in the development of mitigation and response strategies. By way of example, we demonstrate how Panalysis can be used to plan for a 1918-like flu pandemic. We discuss potential future applications of this tool.     

Lung ultrasound: a new tool for the cardiologist

Background

We have previously reported strain dyssynchrony index assessed by two-dimensional speckle tracking strain, and a marker of both dyssynchrony and residual myocardial contractility, can predict response to cardiac resynchronization therapy (CRT). A newly developed three-dimensional (3-D) speckle tracking system can quantify endocardial area change ratio (area strain), which coupled with the factors of both longitudinal and circumferential strain, from all 16 standard left ventricular (LV) segments using complete 3-D pyramidal datasets. Our objective was to test the hypothesis that strain dyssynchrony index using area tracking (ASDI) can quantify dyssynchrony and predict response to CRT.

Methods

We studied 14 heart failure patients with ejection fraction of 27 ± 7% (all≤35%) and QRS duration of 172 ± 30 ms (all≥120 ms) who underwent CRT. Echocardiography was performed before and 6-month after CRT. ASDI was calculated as the average difference between peak and end-systolic area strain of LV endocardium obtained from 3-D speckle tracking imaging using 16 segments. Conventional dyssynchrony measures were assessed by interventricular mechanical delay, Yu Index, and two-dimensional radial dyssynchrony by speckle-tracking strain. Response was defined as a ≥15% decrease in LV end-systolic volume 6-month after CRT.

Results

ASDI ≥ 3.8% was the best predictor of response to CRT with a sensitivity of 78%, specificity of 100% and area under the curve (AUC) of 0.93 (p < 0.001). Two-dimensional radial dyssynchrony determined by speckle-tracking strain was also predictive of response to CRT with an AUC of 0.82 (p < 0.005). Interestingly, ASDI ≥ 3.8% was associated with the highest incidence of echocardiographic improvement after CRT with a response rate of 100% (7/7), and baseline ASDI correlated with reduction of LV end-systolic volume following CRT (r = 0.80, p < 0.001).

Conclusions

ASDI can predict responders and LV reverse remodeling following CRT. This novel index using the 3-D speckle tracking system, which shows circumferential and longitudinal LV dyssynchrony and residual endocardial contractility, may thus have clinical significance for CRT patients.     

SNPicker: a graphical tool for primer picking in designing mutagenic endonuclease restriction assays

Simple, low-cost and accurate genotyping methods for single nucleotide polymorphisms (SNPs) are in high demand in the post-genome-sequencing era. We present a graphical tool called SNPicker, implemented in Java, which significantly facilitates the design of mutagenic endonuclease restriction assays. SNPicker uses the online NEB REBASE to automatically scan for all possible designs of mutagenic primers that can facilitate the picking of mismatched PCR primers to artificially introduce or abolish a restriction site at the target SNP site. We successfully applied SNPicker in designing endonuclease restriction assays for 14 SNPs for the MTHFR gene, the Coagulation Factor II gene and the Coagulation Factor V gene. The SNP assays designed using SNPicker were cross-validated using the MassARRAY technology.     

Quantum dots for tracking cellular transport of lectin-functionalized nanoparticles

Successful drug delivery by functionalized nanocarriers largely depends on their efficient intracellular transport which has not yet been fully understood. We developed a new tracking technique by encapsulating quantum dots into the core of wheat germ agglutinin-conjugated nanoparticles (WGA-NP) to track cellular transport of functionalized nanocarriers. The resulting nanoparticles showed no changes in particle size, zeta potential or biobinding activity, and the loaded probe presented excellent photostability and tracking ability. Taking advantage of these properties, cellular transport profiles of WGA-NP in Caco-2 cells was demonstrated. The cellular uptake begins with binding of WGA to its receptor at the cell surface. The subsequent endocytosis happened in a cytoskeleton-dependent manner and by means of clathrin and caveolae-mediated mechanisms. After endosome creating, transport occurs to both trans-Golgi and lysosome. Our study provides new evidences for quantum dots as a cellular tracking probe of nanocarriers and helps understand intracellular transport profile of lectin-functionalized nanoparticles.     

Quantum dots in bio-imaging: Revolution by the small

Visual analysis of biomolecules is an integral avenue of basic and applied biological research. It has been widely carried out by tagging of nucleotides and proteins with traditional fluorophores that are limited in their application by features such as photobleaching, spectral overlaps, and operational difficulties. Quantum dots (QDs) are emerging as a superior alternative and are poised to change the world of bio-imaging and further its applications in basic and applied biology. The interdisciplinary field of nanobiotechnology is experiencing a revolution and QDs as an enabling technology have become a harbinger of this hybrid field. Within a decade, research on QDs has evolved from being a pure science subject to the one with high-end commercial applications.