Doxorubicin-induced cardiotoxicity: direct correlation of cardiac fibroblast and H9c2 cell survival and aconitase activity with heat shock protein 27

The use of doxorubicin (Dox) and its derivatives as chemotherapeutic drugs to treat patients with cancer causes dilated cardiomyopathy and congestive heart failure due to Dox-induced cardiotoxicity. In this work, using heat shock factor-1 wild-type (HSF-1(+/+)) and HSF-1 knockout (HSF-1(-/-)) mouse fibroblasts and embryonic rat heart-derived cardiac H9c2 cells, we show that the magnitude of protection from Dox-induced toxicity directly correlates with the level of the heat shock protein 27 (HSP27). Western blot analysis of normal and heat-shocked cells showed the maximum expression of HSP27 in heat-shocked cardiac H9c2 cells and no HSP27 in HSF-1(-/-) cells (normal or heat-shocked). Correspondingly, the cell viability, measured [with (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay] after treatment with various concentrations of Dox, was the highest in heat-shocked H9c2 cells and the lowest in HSF-1(-/-) cells. Depleting HSP27 in cardiac H9c2 cells by small interfering (si)RNA also reduced the viability against Dox, confirming that HSP27 does protect cardiac cells against the Dox-induced toxicity. The cells that have lower HSP27 levels such as HSF-1(-/-), were found to be more susceptible for aconitase inactivation. Based on these results we propose a novel mechanism that HSP27 plays an important role in protecting aconitase from Dox-generated O(2)*(-), by increasing SOD activity. Such a protection of aconitase by HSP27 eliminates the catalytic recycling of aconitase released Fe(II) and its deleterious effects in cardiac cells.     

A highly sensitive biocompatible spin probe for imaging of oxygen concentration in tissues

The development of an injectable probe formulation, consisting of perchlorotriphenylmethyl triester radical dissolved in hexafluorobenzene, for in vivo oximetry and imaging of oxygen concentration in tissues using electron paramagnetic resonance (EPR) imaging is reported. The probe was evaluated for its oxygen sensitivity, biostability, and distribution in a radiation-induced fibrosarcoma tumor transplanted into C3H mice. Some of the favorable features of the probe are: a single narrow EPR peak (anoxic linewidth, 41 microT), high solubility in hexafluorobenzene (>12 mM), large linewidth sensitivity to molecular oxygen ( approximately 1.8 microT/mmHg), good stability in tumor tissue (half-life: 3.3 h), absence of spin-spin broadening (up to 12 mM), and lack of power saturation effects (up to 200 mW). Three-dimensional spatial and spectral-spatial (spectroscopic) EPR imaging measurements were used to visualize the distribution of the probe, as well as to obtain spatially resolved pO(2) information in the mice tumor subjected to normoxic and hyperoxic treatments. The new probe should enable unique opportunities for measurement of the oxygen concentration in tumors using EPR methods.     

Bioreduction of hexavalent chromium by <Emphasis Type="Italic">Pseudomonas stutzeri</Emphasis> L1 and <Emphasis Type="Italic">Acinetobacter baumannii</Emphasis> L2

Bioreduction of the very toxic hexavalent chromium ion [Cr(VI)] to the non-toxic trivalent chromium ion [Cr(III)] is a key remediation process in chromium-contaminated sites. In this study, we investigated the bioreduction of Cr(VI) by Pseudomonas stutzeri L1 and Acinetobacter baumannii L2. The optimum pH (5–10), temperature (27, 37 and 60 °C) and initial chromium Cr(VI) concentration (100–1000 mg L^?1) for Cr(VI) reduction by strains L1 and L2 were determined using the diphenylcarbazide method. In the presence of L1 and L2, the bioreduction rate of Cr(VI) was 40–97 and 84–99%, respectively. The bioreduction of Cr(VI) by L2 was higher, reaching up to 84%—than that by L1. The results showed that strain L2 was able to survive even if exposed to 1000 mg L^?1 of Cr(VI) and that this tolerance to the effects of Cr(VI) was linked to the activity of soluble enzyme fractions. Overall, A. baumannii L2 would appear to be a potent Cr(VI)-tolerant candidate for the bioremediation of chromium (VI)-contaminated wastewater effluent.     

In vivo imaging of free radicals: Applications from mouse to man

Free radicals and other paramagnetic species, play an important role in cellular injury and pathophysiology. EPR spectroscopy and imaging has emerged as an important tool for non-invasive in vivo measurement and spatial mapping of free radicals in biological tissues. Extensive applications have been performed in small animals such as mice and recently applications in humans have been performed. Spatial EPR imaging enables 3D mapping of the distribution of a given free radical while spectral-spatial EPR imaging enables mapping of the spectral information at each spatial position, and, from the observed line width, the localized tissue oxygenation can be determined. A variety of spatial, and spectral-spatial EPR imaging applications have been performed. These techniques, along with the use of biocompatible paramagnetic probes including particulate suspensions and soluble nitroxide radicals, enable spatial imaging of the redox state and oxygenation in a variety of biomedical applications. With spectral-spatial EPR imaging, oxygenation was mapped within the gastrointestinal (GI) tract of living mice, enabling measurement of the oxygen gradient from the proximal to the distal GI tract. Using spatial EPR imaging, the distribution and metabolism of nitroxide radicals within the major organs of the body of living mice was visualized and anatomically co-registered by proton MRI enabling in vivo mapping of the redox state and radical clearance. EPR imaging techniques have also been applied to non-invasively measure the distribution and metabolism of topically applied nitroxide redox probes in humans, providing information regarding the penetration of the label through the skin and measurement of its redox clearance. Thus, EPR spectroscopy and imaging has provided important information in a variety of applications ranging from small animal models of disease to topical measurement of redox state in humans.     

Abandoned metalliferous mines: ecological impacts and potential approaches for reclamation

The lack of awareness for timely management of the environment surrounding a metal mine site results in several adverse consequences such as rampant business losses, abandoning the bread-earning mining industry, domestic instability and rise in ghost towns, increased environmental pollution, and indirect long-term impacts on the ecosystem. Although several abandoned mine lands (AMLs) exist globally, information on these derelict mines has not been consolidated in the literature. We present here the state-of-the-art on AMLs in major mining countries with emphasis on their impact towards soil health and biodiversity, remediation methods, and laws governing management of mined sites. While reclamation of metalliferous mines by phytoremediation is still a suitable option, there exist several limitations for its implementation. However, many issues of phytoremediation at the derelict mines can be resolved following phytostabilization, a technology that is effective also at the modern operational mine sites. The use of transgenic plant species in phytoremediation of metals in contaminated sites is also gaining momentum. In any case, monitoring and efficacy testing for bioremediation of mined sites is essential. The approaches for reclamation of metalliferous mines such as environmental awareness, effective planning and assessment of pre- and post-mining activities, implementation of regulations, and a safe and good use of phytostabilizers among the native plants for revegetation and ecological restoration are discussed in detail in the present review. We also suggest the use of microbially-enhanced phytoremediation and nanotechnology for efficient reclamation of AMLs, and identify future work warranted in this area of research. Further, we believe that the integration of science of remediation with mining policies and regulations is a reliable option which when executed can virtually balance economic development and environmental destruction for safer future.     

Enhanced photocatalytic and electrochemical performance of hydrothermally prepared NiO-doped Co nanocomposites

In this study, we synthesize nanostructured nickel oxide (NiO) and doped cobalt (Co) by combining nickel(II) chloride hexahydrate (NiCl₂.6H₂O) and sodium hydroxide (NaOH) as initial substances. We analyzed the characteristics of the product nanostructures, including their structure, optical properties, and magnetic properties, using various techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet absorption spectroscopy (UV–Vis), Fourier transform infrared (FTIR) spectroscopy, and vibrating sample magnetometers (VSM). The NiO nanoparticles doped with Co showed photocatalytic activity in degrading methylene blue (MB) dye in aqueous solutions. We calculated the degradation efficiencies by analyzing the UV–Vis absorption spectra at the dye's absorption wavelength of 664 nm. It was observed that the NiO-doped Co nanoparticles facilitated enhanced recombination and migration of active elements, which led to more effective degradation of organic dyes during photocatalysis. We also assessed the electrochemical properties of the materials using cyclic voltammetry (CV) and impedance spectroscopy in a 1 mol% NaOH solution. The NiO-modified electrode exhibited poor voltammogram performance due to insufficient contact between nanoparticles and the electrolyte solution. In contrast, the uncapped NiO's oxidation and reduction cyclic voltammograms displayed redox peaks at 0.36 and 0.30 V, respectively.     

A short note on oxytocin and stress attenuation

Stress is integral part of life and it initiates appropriate response at times of adversities to promise survival. Stress could be either physiological or psychogenic. Stress is often psychogenic in nature and it induces the release of cortisol from adrenal cortex into circulation by activating Hypo thalamo-pituitary-adrenal axis (HPA). Cortisol thus released mediates the stress response by its catabolic effects to enhance the activity of vital organs during emergency. However, prolonged activation of the HPA axis can lead to physical and mental illness as an outcome of persistent stress. Nature has bestowed the biological system with an array of endogenous mechanisms to buffer stress. Oxytocin, a nano-peptide released by the magno-cellular neurons of hypothalamic paraventricular nucleus (PVN) is an efficient stress buffering neuro-peptide. This hormone mediates many physiological and behavioural functions get released during stress. It attenuates the stress axis initiated by the release of corticotropin releasing hormone (CRH) from the parvocellular neurons of the same hypothalamic nucleus. Oxytocin released by PVN exerts an inhibitory effect on the release of CRH by down-regulating the expression of the gene that transcribes for this hypothalamic hormone. Thus, it inhibits the release of adreno cotico trophic hormone (ACTH) and cortisol, exerting an overall suppressive modulation of the stress axis and attenuates stress.     

Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents

The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC–MS analysis.Abbreviations: ABTS, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid), DPPH, 2,2-diphenyl-1-picrylhydrazyl, GAE, gallic acid equivalent, GC–MS, gas chromatography and mass spectrometry     

<Emphasis Type="Italic">Bacillus rhizosphaerae</Emphasis> sp. nov., an novel diazotrophic bacterium isolated from sugarcane rhizosphere soil

A Gram-positive, non-pigmented, rod-shaped, diazotrophic bacterial strain, designated SC-N012^T, was isolated from rhizosphere soil of sugarcane and was subjected to a polyphasic taxonomic study. The strain exhibited phenotypic properties that included chemotaxonomic characteristics consistent with its classification in the genus Bacillus. Sequence analysis of the 16S rRNA gene of SC-N012^T revealed the closest match (98.9% pair wise similarity) with Bacillus clausii DSM 8716^T. However, DNA–DNA hybridization experiments indicated low levels of genomic relatedness (32%) with this strain. The major components of the fatty acid profile are iso-C_15:0, anteiso-C_15:0, iso-C_17:0 and anteiso-C_17:0. The diagnostic cell-wall diamino acid was meso-diaminopimelic acid. The G+C content of the genomic DNA is 43.0 mol%. The lipids present in strain SC-N012^T are diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol and two unknown phospholipids. Their predominant respiratory quinone was MK-7. Studies of DNA-DNA relatedness, morphological, physiological and chemotaxonomic analyses and phylogenetic data based on 16S rRNA gene sequencing allowed strain SC-N012^T to be described as members of novel species of the genus Bacillus, for which the name Bacillus rhizosphaerae sp. nov. is proposed. The type strain is SC-N012^T (=DSM 21911^T = NCCB 100267^T).