Isolation of an exopolysaccharide-producing heavy metal-resistant Halomonas sp. MG.

An exopolysaccharide (EPS)-producing heavy metal-resistant Gram-negative bacterium was isolated from ore-contaminated soil. The selected strain was identified by 16S rDNA sequencing and designated as Halomonas sp. MG. Phylogenetic analysis of the gene sequence showed its close similarity with Halomonas sp. Field emission scanning electron microscopy analysis revealed that the EPS had a porous structure with small pores. X-ray diffractograms showed the non-crystalline nature of the EPS. Further, FTIR spectroscopic analysis revealed the presence of carboxyl, hydroxyl and amide groups corresponding to a typical EPS.

Synergistic effect of chelators and Herbaspirillum sp. GW103 on lead phytoextraction and its induced oxidative stress in Zea mays.

Phytoremediation is an in situ, low-cost strategy for cleanup of the sites contaminated with heavy metals. Experiments were conducted to assess the impact of synthetic chelators and plant growth-promoting rhizosphere bacteria (Herbaspirillum sp. GW103) on heavy metal lead (Pb) uptake in Z. mays cultivated in Pb-contaminated soil. The present study investigated the Pb phytoaccumulation rate and plant antioxidant enzyme activities in Z. mays exposed to 100 mg/kg of PbNO3. The combination of gluconic acid (GA) with Herbaspirillum sp. GW103 treatment showed higher Pb solubility (18.9 mg/kg) compared with other chelators. The chemical chelators showed the significant difference in phytoaccumulation as well as antioxidant enzyme activities. The antioxidant enzymes such as catalase, peroxidase and superoxide dismutase activities changed under Pb stress. The study indicated that increased activity of antioxidant enzymes may play as signal inducers to fight against Pb.

Isolation and Characterization of Multi-Metal-Resistant Halomonas sp. MG from Tamil Nadu Magnesite Ore Soil in India.

The aim of the study was to isolate and characterize potential multi-metal-resistant bacteria from ore soils. A total of three bacteria were isolated and assayed for resistance to arsenic (As), copper (Cu), and lead (Pb). Isolate Halomonas sp. MG exhibited maximum resistance to 1000 mg Pb/L, 800 mg As/L, and 500 mg Cu/L and it was identified as Halomonas sp. based on the partial 16S rDNA sequences. The metal(loid)s resistance mechanisms were further confirmed by amplification of arsC (As) copAU (Cu), and pbrT (Pb) genes. Biological transmission electron micrographs and XRD studies showed that the isolate Halomonas sp. MG transformed and/or biomineralized the metals either intracellularly or extracellularly. These results suggest that the isolate could be used as a potential candidate for the bioremediation of As, Cu, and Pb.

Spinal pathways involved in somatosensory inhibition of the psychomotor actions of cocaine.

Previous studies have demonstrated that somatosensory stimuli influence dopamine transmission in the mesolimbic reward system and can reduce drug-induced motor behaviors, craving and dependence. Until now, the central links between somatosensory and brain reward systems are not known. Here, we show that the dorsal column (DC) somatosensory pathway contains projections that convey an inhibitory input from the periphery to mesolimbic reward circuits. Stimulation of the ulnar nerve under HT7 acupoint suppressed psychomotor response to cocaine, which was abolished by disruption of the DC pathway, but not the spinothalamic tract (STT). Low-threshold or wide-dynamic range neurons in the cuneate nucleus (CN) were excited by peripheral stimulation. Lesions of dorsal column or lateral habenula (LHb) prevented the inhibitory effects of peripheral stimulation on cocaine-induced neuronal activation in the nucleus accumbens (NAc). LHb neurons projecting to the ventral tegmental area (VTA)/rostromedial tegmental nucleus (RMTg) regions were activated by peripheral stimulation and LHb lesions reversed the inhibitory effects on cocaine locomotion produced by peripheral stimulation. These findings suggest that there exists a pathway in spinal cord that ascends from periphery to mesolimbic reward circuits (spino-mesolimbic pathway) and the activation of somatosensory input transmitted via the DC pathway can inhibit the psychomotor response to cocaine.

An integrative model of workplace self-protective behavior for Korean nurses.

PURPOSE: This study was conducted to develop and test a hypothetical stage model of workplace self-protective behaviors with respect to blood transmitted infections and musculoskeletal injuries for Korean nurses. METHODS: A nonexperimental, cross-sectional study design was adopted. The study participants were 320 nurses at two Korean university hospitals. Perceived sensitivity, severity, barriers, benefits, self-efficacy, social support, and safety climate were assessed. RESULTS: Overall, fit indicators showed a good fit for the hypothetical model of self-protective behaviors against blood transmitted infections and musculoskeletal injuries. The significant factors of self-protective behaviors against blood transmitted infections were perceived barriers and social support. The significant factors of self-protective behaviors against musculoskeletal injuries were perceived benefits, barriers, and self-efficacy. CONCLUSION: Our findings suggest that the significant psychosocial constructs of stages of self-protective behavior are dependent on health problem type. Accordingly, we advise that characteristics of behavior and types of disease and health problem should be given priority when developing intervention programs for particular self-protective health behaviors.

Peripheral afferent mechanisms underlying acupuncture inhibition of cocaine behavioral effects in rats.

Administration of cocaine increases locomotor activity by enhancing dopamine transmission. To explore the peripheral mechanisms underlying acupuncture treatment for drug addiction, we developed a novel mechanical acupuncture instrument (MAI) for objective mechanical stimulation. The aim of this study was to evaluate whether acupuncture inhibition of cocaine-induced locomotor activity is mediated through specific peripheral nerves, the afferents from superficial or deep tissues, or specific groups of nerve fibers. Mechanical stimulation of acupuncture point HT7 with MAI suppressed cocaine-induced locomotor activity in a stimulus time-dependent manner, which was blocked by severing the ulnar nerve or by local anesthesia. Suppression of cocaine-induced locomotor activity was elicited after HT7 stimulation at frequencies of either 50 (for Meissner corpuscles) or 200 (for Pacinian corpuscles) Hz and was not affected by block of C/Aδ-fibers in the ulnar nerve with resiniferatoxin, nor generated by direct stimulation of C/Aδ-fiber afferents with capsaicin. These findings suggest that HT7 inhibition of cocaine-induced locomotor activity is mediated by A-fiber activation of ulnar nerve that originates in superficial and deep tissue.