Willingness to spare animals in undergraduate medical education in Southern India: a preliminary questionnaire-based investigation

Animal experiments continue to play an integral role in Indian undergraduate medical education, even though alternatives are becoming increasingly available. In this context, this study aimed to assess the perceptions of pharmacology faculty members from medical colleges in southern India regarding the use of animals and alternatives in experimental pharmacology, and to determine the association between these perceptions and the socio-demographic characteristics of the participants. Data were collected from 59 faculty members of 15 medical colleges in southern India. The response rate was 84.3%. A 30-statement, five-domain questionnaire was used, with a global score of 120. The mean ± SD global score was 60.9 ± 17.3. Significant differences were observed in domain scores and individual statement scores with respect to the extent of teaching experience. There were no statistically significant differences in perceptions with respect to age, gender or educational qualifications. All the participating colleges were conducting at least 3-8 animal experiments per year on the rabbit, rat, mouse and frog/toad. The pharmacology faculty members in the southern India medical colleges included in the study (especially the more experienced teachers) supported animal use in undergraduate medical education, in spite of being aware of the drawbacks of animal experiments and the availability of alternatives.     

Tetrahydroindazole inhibitors of bacterial type II topoisomerases. Part 2: SAR development and potency against multidrug-resistant strains

We have previously reported a novel class of tetrahydroindazoles that display potency against a variety of Gram-positive and Gram-negative bacteria, potentially via interaction with type II bacterial topoisomerases. Herein are reported SAR investigations of this new series. Several compounds possessing broad-spectrum potency were prepared. Further, these compounds exhibit activity against multidrug-resistant Gram-positive microorganisms equivalent to that against susceptible strains.     

The Drosophila tumor suppressors Expanded and Merlin differentially regulate cell cycle exit, apoptosis, and Wingless signaling

Mutations that inactivate either merlin (mer) or expanded (ex) result in increased cell growth and proliferation in Drosophila. Both Mer and Ex are members of the Band 4.1 protein superfamily, and, based on analyses of mer ex double mutants, they are proposed to function together in at least a partially redundant manner upstream of the Hippo (Hpo) and Warts (Wts) proteins to regulate cell growth and division. By individually analyzing ex and mer mutant phenotypes, we have found important qualitative and quantitative differences in the ways Mer and Ex function to regulate cell proliferation and cell survival. Though both mer and ex restrict cell and tissue growth, ex clones exhibit delayed cell cycle exit in the developing eye, while mer clones do not. Conversely, loss of mer substantially compromises normal developmental apoptosis in the pupal retina, while loss of ex has only mild effects. Finally, ex has a role in regulating Wingless protein levels in the eye that is not obviously shared by either mer or hpo. Taken together, our data suggest that Mer and Ex differentially regulate multiple downstream pathways.     

Macrophomina phaseolina: microbased biorefinery for gold nanoparticle production

Biofabrication of nanoparticles via the principles of green nanotechnology is a key issue addressed in nanobiotechnology research. There is a growing need for development of a synthesis method for producing biocompatible stable nanoparticles in order to avoid adverse effects in medical applications. We report the use of simple and rapid biosynthesis method for the preparation of gold nanoparticles using Macrophomina phaseolina (Tassi) Goid, a soil-borne pathogen. The effect of pH and temperature on the synthesis of gold nanoparticles by M. phaseolina was also assessed. Different techniques like UV-Visible Spectroscopy, Transmission Electron Microscopy (TEM), Dynamic light scattering (DLS) measurements, Fourier transform infrared (FTIR), and EDX were used to characterize the gold nanoparticles. The movement of these gold nanoparticles inside Escherichia coli (ATCC11103) along with effect on growth and viability was evaluated. The biogenic gold nanoparticle was synthesized at 37 °C temperature and neutral pH. UV-Visible Spectroscopy, TEM, EDX, and DLS measurements confirm the formation of 14 to 16 nm biogenic gold nanoparticles. FTIR substantiates the presence of protein capping on Macrophomina phaseolina-mediated gold nanoparticles. The non-toxicity of gold nanoparticles was confirmed by the growth and viability assay while the TEM images validated the entry of gold nanoparticles without disrupting the structural integrity of E. coli. Biogenic method for the synthesis of nanoparticles using fungi is novel, efficient, without toxic chemicals. These biogenic gold nanoparticles themselves are nontoxic to the microbial cells and offer a better substitute for drug delivery system.

     

Regulation of Fc?RI Signaling in Mast Cells by G Protein-coupled Receptor Kinase 2 and Its RH Domain

Agonist-induced phosphorylation of G protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) promotes their desensitization and internalization. Here, we sought to determine the role of GRK2 on FcϵRI signaling and mediator release in mast cells. The strategies utilized included lentiviral shRNA-mediated GRK2 knockdown, GRK2 gene deletion (GRK2^flox/flox/cre recombinase) and overexpression of GRK2 and its regulator of G protein signaling homology (RH) domain (GRK2-RH). We found that silencing GRK2 expression caused ∼50% decrease in antigen-induced Ca²⁺ mobilization and degranulation but resulted in ablation of cytokine (IL-6 and IL-13) generation. The effect of GRK2 on cytokine generation does not require its catalytic activity but is mediated via the phosphorylation of p38 and Akt. Overexpression of GRK2 or its RH domain (GRK2-RH) enhanced antigen-induced mast cell degranulation and cytokine generation without affecting the expression levels of any of the FcϵRI subunits (α, β, and γ). GRK2 or GRK2-RH had no effect on antigen-induced phosphorylation of FcϵRIγ or Src but enhanced tyrosine phosphorylation of Syk. These data demonstrate that GRK2 modulates FcϵRI signaling in mast cells via at least two mechanisms. One involves GRK2-RH and modulates tyrosine phosphorylation of Syk, and the other is mediated via the phosphorylation of p38 and Akt.     

An Efficient Wavelet-Based Approximation Method to Gene Propagation Model Arising in Population Biology

In this paper, we have applied an efficient wavelet-based approximation method for solving the Fisher’s type and the fractional Fisher’s type equations arising in biological sciences. To the best of our knowledge, until now there is no rigorous wavelet solution has been addressed for the Fisher’s and fractional Fisher’s equations. The highest derivative in the differential equation is expanded into Legendre series; this approximation is integrated while the boundary conditions are applied using integration constants. With the help of Legendre wavelets operational matrices, the Fisher’s equation and the fractional Fisher’s equation are converted into a system of algebraic equations. Block-pulse functions are used to investigate the Legendre wavelets coefficient vectors of nonlinear terms. The convergence of the proposed methods is proved. Finally, we have given some numerical examples to demonstrate the validity and applicability of the method.     

Antagonistic potential of native strain Streptomyces aurantiogriseus VSMGT1014 against sheath blight of rice disease

A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, India, among which 57 showed antagonistic activity towards Rhizoctonia solani, which is sheath blight (ShB) pathogen of rice and other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata with a variable zone of inhibition. Potential actinomycete strain VSMGT1014 was identified as Streptomyces aurantiogriseus VSMGT1014 based on the morphological, physiological, biochemical and 16S rRNA sequence analysis. The strain VSMGT1014 produced lytic enzymes, secondary metabolites, siderophore, volatile substance and indole acetic acid. Crude metabolites of VSMGT1014 showed activity against R. solani at 5 µg ml^?1; however, the prominent inhibition zone was observed from 40 to 100 µg ml^?1. Reduced lesion heights observed in culture, cells-free filtrate, crude metabolites and carbendazim on challenge with pathogen in the detached leaf assay. The high content screening test clearly indicated denucleation of R. solani at 5 µg ml^?1 treatment of crude metabolite and carbendazim respectively. The results conclude that strain VSMGT1014 was found to be a potential candidate for the control of ShB of rice as a bio fungicide.     

Differences in levels of the transmembrane protein Crumbs can influence cell survival at clonal boundaries

The survival and growth of individual cells in a tissue can be nonautonomously regulated by the properties of adjacent cells. In mosaic Drosophila imaginal discs, for example, wild-type cells induce the elimination of adjacent slow-growing Minute cells by apoptosis, while, conversely, certain types of faster-growing cells are able to eliminate adjacent wild-type cells. This process, known as cell competition, represents one example of a diverse group of phenomena in which short-range heterotypic interactions result in the selective elimination of one type of cell by another. The mechanisms that designate "winner" and "loser" genotypes in these processes are not known. Here we show that apoptosis is observed preferentially at boundaries that separate populations of cells that express different levels of the transmembrane protein Crumbs (Crb). Cells that express higher levels of Crb tend to be eliminated when they are near cells that express lower levels of Crb. We also observe distortions in the structure of epithelia on either side of boundaries between populations of cells that differ in Crb expression. Thus, while previous studies have focused mostly on the cell autonomous functions of Crb, we show that Crb can regulate cell survival and tissue morphology nonautonomously. Moreover, we find that the extracellular domain (ECD) of Crb, which seems to be dispensable for some of the other characterised functions of Crb, is required to elicit the nonautonomous effects on cell survival. The ECD can also regulate the subcellular localisation of Hippo pathway components, and possibly other proteins, in adjacent cells and may therefore directly mediate these effects. Several genetic lesions alter Crb levels, including loss-of-function mutations in hyperplastic tumour suppressors in the Hippo-Salvador-Warts pathway and in neoplastic tumour suppressor genes, such as scribble. Thus, Crb may be part of a "surveillance mechanism" that is responsible for the cell death that is observed at the boundaries of mutant clones in these cases.     

Magnetic resonance imaging of glutamate

Glutamate, a major neurotransmitter in the brain, shows a pH- and concentration-dependent chemical exchange saturation transfer effect (GluCEST) between its amine group and bulk water, with potential for in vivo imaging by nuclear magnetic resonance. GluCEST asymmetry is observed ～3 p.p.m. downfield from bulk water. Middle cerebral artery occlusion in the rat brain resulted in an ～100% elevation of GluCEST in the ipsilateral side compared with the contralateral side, predominantly owing to pH changes. In a rat brain tumor model with blood-brain barrier disruption, intravenous glutamate injection resulted in a clear elevation of GluCEST and a similar increase in the proton magnetic resonance spectroscopy signal of glutamate. GluCEST maps from healthy human brain were also obtained. These results demonstrate the feasibility of using GluCEST for mapping relative changes in glutamate concentration, as well as pH, in vivo. Contributions from other brain metabolites to the GluCEST effect are also discussed.