Renu Singh

Drought susceptibility of modern rice varieties: an effect of linkage of drought tolerance with undesirable traits.

Green Revolution (GR) rice varieties are high yielding but typically drought sensitive. This is partly due to the tight linkage between the loci governing plant height and drought tolerance. This linkage is illustrated here through characterization of qDTY1.1, a QTL for grain yield under drought that co-segregates with the GR gene sd1 for semi-dwarf plant height. We report that the loss of the qDTY1.1 allele during the GR was due to its tight linkage in repulsion with the sd1 allele. Other drought-yield QTLs (qDTY) also showed tight linkage with traits rejected in GR varieties. Genetic diversity analysis for 11 different qDTY regions grouped GR varieties separately from traditional drought-tolerant varieties, and showed lower frequency of drought tolerance alleles. The increased understanding and breaking of the linkage between drought tolerance and undesirable traits has led to the development of high-yielding drought-tolerant dwarf lines with positive qDTY alleles and provides new hope for extending the benefits of the GR to drought-prone rice-growing regions.

Responding to the challenge of untreatable gonorrhea: ETX0914, a first-in-class agent with a distinct mechanism-of-action against bacterial Type II topoisomerases.

With the diminishing effectiveness of current antibacterial therapies, it is critically important to discover agents that operate by a mechanism that circumvents existing resistance. ETX0914, the first of a new class of antibacterial agent targeted for the treatment of gonorrhea, operates by a novel mode-of-inhibition against bacterial type II topoisomerases. Incorporating an oxazolidinone on the scaffold mitigated toxicological issues often seen with topoisomerase inhibitors. Organisms resistant to other topoisomerase inhibitors were not cross-resistant with ETX0914 nor were spontaneous resistant mutants to ETX0914 cross-resistant with other topoisomerase inhibitor classes, including the widely used fluoroquinolone class. Preclinical evaluation of ETX0914 pharmacokinetics and pharmacodynamics showed distribution into vascular tissues and efficacy in a murine Staphylococcus aureus infection model that served as a surrogate for predicting efficacious exposures for the treatment of Neisseria gonorrhoeae infections. A wide safety margin to the efficacious exposure in toxicological evaluations supported progression to Phase 1. Dosing ETX0914 in human volunteers showed sufficient exposure and minimal adverse effects to expect a highly efficacious anti-gonorrhea therapy.

Ferromagnetic CaRuO 3

The non-magnetic and non-Fermi-liquid CaRuO3 is the iso-structural analog of the ferromagnetic (FM) and Fermi-liquid SrRuO3. We show that an FM order in the orthorhombic CaRuO3 can be established by the means of tensile epitaxial strain. The structural and magnetic property correlations in the CaRuO3 films formed on SrTiO3 (100) substrate establish a scaling relation between the FM moment and the tensile strain. The strain dependent crossover from non-magnetic to FM CaRuO3 was observed to be associated with switching of non-Fermi liquid to Fermi-liquid behavior. The intrinsic nature of this strain-induced FM order manifests in the Hall resistivity too; the anomalous Hall component realizes in FM tensile-strained CaRuO3 films on SrTiO3 (100) whereas the non-magnetic compressive-strained films on LaAlO3 (100) exhibit only the ordinary Hall effect. These observations of an elusive FM order are consistent with the theoretical predictions of scaling of the tensile epitaxial strain and the magnetic order in tensile CaRuO3. We further establish that the tensile strain is more efficient than the chemical route to induce FM order in CaRuO3.

Rapid and PCR-free DNA Detection by Nanoaggregation-Enhanced Chemiluminescence

The aggregation of gold nanoparticles (AuNPs) is known to induce an enhancement of localized surface plasmon resonance due to the coupling of plasmonic fields of adjacent nanoparticles. Here we show that AuNPs aggregation also causes a significant enhancement of chemiluminescence in the presence of luminophores. The phenomenon is used to introduce a rapid and sensitive DNA detection method that does not require amplification. DNA probes conjugated to AuNPs were used to detect a DNA target sequence specific to the fungus Ceratocystis fagacearum, causal agent of oak wilt. The hybridization of the DNA target with the DNA probes results in instantaneous aggregation of AuNPs into nanoballs, leading to a significant enhancement of luminol chemiluminescence. The enhancement reveals a linear correlation (R2u2009=u20090.98) to the target DNA concentration, with a limit of detection down to 260u2009fM (260u2009×u200910−15u2009M), two orders of magnitude higher than the performance obtained with plasmonic colorimetry and absorption spectrometry of single gold nanoparticles. Furthermore, the detection can be performed within 22u2009min using only a portable luminometer.

Effects of Carbon Dioxide Aerosols on the Viability of Escherichia coli during Biofilm Dispersal.

A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces. However, the impact of the aerosols on the viability of bacteria during treatment has never been evaluated. In this study, the effects of high-speed CO2 aerosols, a mixture of solid and gaseous CO2, on bacteria viability was studied. It was found that when CO2 aerosols were used to disperse biofilms of Escherichia coli, they led to a significant loss of viability, with approximately 50% of the dispersed bacteria killed in the process. By comparison, 75.6% of the biofilm-associated bacteria were viable when gently dispersed using Proteinase K and DNase I. Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet. In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm. As such, these CO2 aerosols not only remove biofilm-associated bacteria effectively but also significantly impact their viability by disrupting membrane integrity.

Electrochemical Immunosensors: Fundamentals and Applications in Clinical Diagnostics

Abstract Immunosensors are the affinity-based biosensing devices that have enormous potential for the next-generation bioanalytical systems. Usually, the components of these self-content devices include biorecognition element, transducers, and the readout systems, where biorecognition systems perceive the physical signals, transducers convert observed input to the quantifiable electrical signals, and the readout systems show the measured signals. For immunosensing, various transducers are used, including electrochemical, optical, and piezoelectric. Usually, these transducers are modified before using in immunosensing platforms, which essentially works on the formation of antigen–antibody complexes. Among all types of the immunosensors, electrochemical immunosensors are widely accepted because of its specificity and high accuracy. Such immunosensors are usually assessed by various bioanalytical techniques for its diagnostic performances. This chapter summarizes the analytical techniques that are generally used to characterize the electrochemical immunosensors and various advanced approaches, i.e., electrochemical lateral flow assays, colorimetric immunosensing, redox cycling, and receptor–ligand–receptor binding bifunctional signal amplification–based approaches have been described with adequate numbers of illustrations. In addition to this, it also highlights various applications of electrochemical immunosensors in clinical diagnostics.

Nanobiosensing Technologies for Prostate Cancer Diagnostics/Prognostics: Tiny Smart Medicine

The widespread incidence of disease, high death rate, and relapse has significantly increased the concern for development of better cancer diagnosis and treatment. Breast cancer being the most prevalent form of cancer among women, prostate cancer (PCa) has turned out to be one of the most common lethal cancer type among men aged 50–80 years old. Tumors develop in the prostate gland of the male reproductive system causing significant pain during urinating and sexual intercourse. Other than lung and skin cancer, prostate cancer is the most common cancer prevalent among American men. As per American Cancer Society’s estimate for prostate cancer, there are ~180,890 new cases and ~26,120 deaths in the United States for year 2016. According to recent statistics, ~1 out of 7 men will be diagnosed with prostate cancer during his lifetime. PCa is very difficult to detect in its early stage which is the cause for increased mortality rates every year. Hence, in such a condition where there is an alarming increase of PCa cases, it is important that the disease is accurately detected at an early stage to improve patient outcomes in terms of morbidity, mortality, and relapse. This demands for an effective diagnosis and prognosis tools with improved sensitivity and specificity towards PCa.

Nano-Enabled Sensing Platforms for Personalized Care

The present book chapter concerns the recent developments of nano-sensing platforms based biosensors for personalized health care as is currently of prime interest to circumvent the delay in diagnosis. Exploiting the burgeoning traits of nanomaterials i.e. high surface to volume ratio, enhanced electron transfer, extraordinary optical, magnetic, and electrical properties improve chances for the transduction technology development. Efforts have been made to discuss the importance of various nanomaterials used with several techniques i.e. electrochemical, magneto-resistance, localized surface plasmon resonance, surface-enhanced Raman scattering, fluorescence; for biosensor construction towards their applications to personalized health care, which is still a “Holy Grail”.

Giant ferromagnetism and exchange bias in tensile strained and Cr modified CaRuO3 thin films

We present an unified approach of epitaxial strain and chemical substitution to induce ferromagnetic order in otherwise non-magnetic CaRuO3. The tensile and compressive strained CaRu1−xCrxO3 (0u2009<u2009xu2009≤u20090.2) (CRCO) films deposited on SrTiO3 (100) and LaAlO3 (100) substrates, respectively, exhibit a magnetic moment larger than their bulk compositions. The compressive strained xu2009=u20090.15 film displays unusually large magnetic moment ∼1.4u2009μB/f.u. which is about one order of magnitude larger than that of its bulk counterpart. We show that this giant magnetic moment manifests in the realization of (i) a giant exchange bias of ∼700u2009Oe in CaRu0.85Cr0.15O3/Pr0.5Ca0.5MnO3 bilayer and (ii) a large hysteretic magnetoresistance; both potential attributes for the spintronic applications.

Ridge Planted Pigeonpea and Furrow Planted Rice in an Intercropping System as Affected by Nitrogen and Weed Management

Intercropping is a crop management system involving the growing of two or more dissimilar crops in distinct row combinations simultaneously on the same land area. In intercropping, the component crop species are usually sown in parallel lines enabling mechanical crop production, maintenance, and harvest. Intercropping involves crop intensification in respect to both time and space dimensions (Ahlawat and Sharma, 2002). Conceptually, an intercropping system helps for risk avoidance from epidemic of insect-pest and diseases and overcome adverse environmental conditions in agro-climatologically unstable regions along with increasing solar radiation utilization and inputs including fertilizer and water utilization compared to monoculture crops. Intercropping not only reduces the risk associated with input costs but also increases profit potential (Rathi and Verma, 1979). Moreover, it provides several major advantages namely, diversification reduces risk associated with crop failure, increased productivity per unit area and time, offers greater yield stability and utilizes the available growth resources more efficiently and sustainably. Furthering rationales of this practice, it caters to the multiple needs of the farmer, is a self-provisioning device, is a mechanism to spread labour peaks, and keeps weeds under check (Singh and Jha, 1984). A number of researchers (Enyi, 1973; Sengupta et al., 1985) reported greater land use efficiency utilizing intercropping and reductions of weed growth through competition. The yield advantage obtained through intercropping has been reported mainly due to efficient utilization and optimization of available natural growth