Augmented Phytoextraction of Lead (Pb2+)-Polluted Soils: A Comparative Study of the Effectiveness of Plant Growth Regulators,EDTA, and Plant Growth–Promoting Rhizobacteria

Abstract

The role of gibberellic acid (GA3), indole-3-acetic acid (IAA), plant growth–promoting bacteria (Rhizobium and Azotobacter), and a synthetic chelator (EDTA; ethylenediaminetetraacetic acid) in lead (Pb) phytoextraction was evaluated using Parthenium hysterophorus (dicot, unpalatable noncrop) and Zea mays (monocot food/forage crop) plants at the flowering stage. Various plant parts were analyzed by atomic absorption/flame spectrophotometer for their Pb content. Both plant growth regulators and both growth-promoting bacteria significantly increased the plant growth in Pb-polluted soils, whereas EDTA significantly decreased growth and biomass of both plants. EDTA increased the Pb uptake (μg g^?1 dry biomass), but the total plant Pb accumulation was decreased. GA3 and IAA significantly increased both uptake and translocation, and the maximum total Pb in the entire plant of Parthenium was found with GA3 foliar spray, whereas in Z. mays the total Pb was maximum in the plant treated with GA3 in combination with EDTA, followed by the GA3 foliar spray treatment. Overall, the GA3 foliar application showed superior response compared with all other treatments. Further research is recommended to observe the role of endogenous GA3 levels in correlation with metal phytoextraction in different plants.     

Protein unfolding studies of thiol-proteinase inhibitor from goat (<Emphasis Type="Italic">Capra hircus</Emphasis>) muscle in the presence of urea and GdnHCl as denaturants

In recent years, many advances have been made in the understanding of functional and structural characteristics of protein evolution from denaturant-based studies that subject the protein to a change in the microenvironment. This paper reports the chemical denaturation of purified goat muscle cystatin (GMC) a thiol-proteinase inhibitor, using urea and guanidine hydrochloride (GdnHCl). The subtle conformational changes of GMC were monitored by intrinsic fluorescence, extrinsic fluorescence, and CD spectroscopic techniques. Further, the activity of GMC as a function of increasing concentration of denaturants was also studied. It was found that increasing the concentration of GdnHCl significantly enhances the inactivation and unfolding of the inhibitor (GMC). In urea-induced denaturation, the intrinsic and extrinsic fluorescence intensity reveals significant structural changes in the inhibitor. Further, it was found that at low concentrations of urea, up to 0.5–1.0 M, there was quenching of fluorescence intensity compared with the native form and a red shift of 5 nm was observed up to 5–8 M. The results presented in this paper suggest that GdnHCl-induced denaturation of GMC follows a simple two-state rule in which native → denatured state transition occurs in a single step. However denaturation with urea proceeds through an intermediate or non-native state.     

Ageing,Neuronal Connectivity and Brain Disorders: An Unsolved Ripple Effect

Cognitive decline associated with ageing and age-related disorders emerges as one of the greatest health challenges in the next decades. To date, the molecular mechanisms underlying the onset of neuronal physiological changes in the central nervous system remain unclear. Functional MRI and PET studies have indicated the decline in working memory performance in older adults. Similarly, age-related disorders, such as Alzheimer’s disease, are associated with changes in the prefontral cortex and related neural circuitry, which underlines the decline of integrative function between different brain regions. This is mainly attributed to the loss of synaptic connectivity, which is a feature commonly observed in neurodegenerative disorders. In humans, the morphological and functional changes in neurons, such as reduction of spine numbers and synaptic dysfunction, precede the first signs of cognitive decline and likely contribute to pathology progression. Thus, a new scenario emerges in which apparently unrelated diseases present common features, such as the remodelling of neuronal circuitries promoted by ageing. For many years, ageing was considered a process of slow deterioration triggered by accidental environmental factors. Conversely, it is now evident that ageing is a biological process tightly controlled by evolutionary highly conserved signalling pathways. Importantly, genetic mutations that enhance longevity significantly delay the loss of synaptic connectivity and, therefore, the onset of age-related brain disorders. Accordingly, tweaking ageing might be an attractive approach to prevent cognitive decline caused by age-related synaptic dysfunction.     

Water-Pipe Smoking and Albuminuria: New Dog with Old Tricks

Water-pipe (WP) smoking is on rise worldwide for the past few years, particularly among younger individuals. Growing evidence indicates that WP smoking is as harmful as cigarette smoking. To date, most of the research has focused on acute health effects of WP smoking, and evidence remains limited when it comes to chronic health effects in relation to long-term WP smoking. Therefore, the aim of this study was to examine the association between WP smoking and albuminuria in apparently healthy individuals. This analysis was conducted on data of a population-based cross-sectional study—the Urban Rural Chronic Diseases Study (URCDS). The study sample was recruited from three sites in Pakistan. Trained nurses carried out individual interviews and obtained the information on demographics, lifestyle factors, and past and current medical history. Measurements of complete blood count, lipid profile, fasting glucose level, and 24-hour albuminuria were also made by using blood and urine samples. Albumin excretion was classified into three categories using standard cut-offs: normal excretion, high-normal excretion and microalbuminuria. Multiple logistic regression models were used to examine the relationship between WP smoking and albuminuria. The final analysis included data from 1,626 health individuals, of which 829 (51.0%) were males and 797 (49.0%) females. Of 1,626 individuals, 267 (16.4%) were current WP smokers and 1,359 (83.6%) were non-WP smokers. WP smoking was significantly associated with high-normal albuminuria (OR  =  2.33, 95% CI 1.68-3.22, p-value <0.001) and microalbuminuria (OR  =  1.75, 95% CI 1.18-2.58, p-value 0.005) after adjustment for age, sex, BMI, social class, hypertension, and diabetes mellitus. WP smoking was significantly associated with high-normal albuminuria and microalbuminuria when analysis was stratified on hypertension and diabetes mellitus categories. WP smoking has a strong association with albuminuria in apparently healthy individuals. More research is warranted to evaluate the temporality of this association between WP smoking and albuminuria.     

Alginate Oligosaccharides Inhibit Fungal Cell Growth and Potentiate the Activity of Antifungals against Candida and Aspergillus spp

The oligosaccharide OligoG, an alginate derived from seaweed, has been shown to have anti-bacterial and anti-biofilm properties and potentiates the activity of selected antibiotics against multi-drug resistant bacteria. The ability of OligoG to perturb fungal growth and potentiate conventional antifungal agents was evaluated using a range of pathogenic fungal strains. Candida (n = 11) and Aspergillus (n = 3) spp. were tested using germ tube assays, LIVE/DEAD staining, scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-throughput minimum inhibition concentration assays (MICs). In general, the strains tested showed a significant dose-dependent reduction in cell growth at ≥6% OligoG as measured by optical density (OD₆₀₀; P<0.05). OligoG (>0.5%) also showed a significant inhibitory effect on hyphal growth in germ tube assays, although strain-dependent variations in efficacy were observed (P<0.05). SEM and AFM both showed that OligoG (≥2%) markedly disrupted fungal biofilm formation, both alone, and in combination with fluconazole. Cell surface roughness was also significantly increased by the combination treatment (P<0.001). High-throughput robotic MIC screening demonstrated the potentiating effects of OligoG (2, 6, 10%) with nystatin, amphotericin B, fluconazole, miconazole, voriconazole or terbinafine with the test strains. Potentiating effects were observed for the Aspergillus strains with all six antifungal agents, with an up to 16-fold (nystatin) reduction in MIC. Similarly, all the Candida spp. showed potentiation with nystatin (up to 16-fold) and fluconazole (up to 8-fold). These findings demonstrate the antifungal properties of OligoG and suggest a potential role in the management of fungal infections and possible reduction of antifungal toxicity.     

Unusual dengue virus 3 epidemic in Nicaragua, 2009

The four dengue virus serotypes (DENV1-4) cause the most prevalent mosquito-borne viral disease affecting humans worldwide. In 2009, Nicaragua experienced the largest dengue epidemic in over a decade, marked by unusual clinical presentation, as observed in two prospective studies of pediatric dengue in Managua. From August 2009-January 2010, 212 dengue cases were confirmed among 396 study participants at the National Pediatric Reference Hospital. In our parallel community-based cohort study, 170 dengue cases were recorded in 2009-10, compared to 13-65 cases in 2004-9. In both studies, significantly more patients experienced "compensated shock" (poor capillary refill plus cold extremities, tachycardia, tachypnea, and/or weak pulse) in 2009-10 than in previous years (42.5% [90/212] vs. 24.7% [82/332] in the hospital study (p<0.001) and 17% [29/170] vs. 2.2% [4/181] in the cohort study (p<0.001). Signs of poor peripheral perfusion presented significantly earlier (1-2 days) in 2009-10 than in previous years according to Kaplan-Meier survival analysis. In the hospital study, 19.8% of subjects were transferred to intensive care, compared to 7.1% in previous years - similar to the cohort study. DENV-3 predominated in 2008-9, 2009-10, and 2010-11, and full-length sequencing revealed no major genetic changes from 2008-9 to 2010-11. In 2008-9 and 2010-11, typical dengue was observed; only in 2009-10 was unusual presentation noted. Multivariate analysis revealed only "2009-10" as a significant risk factor for Dengue Fever with Compensated Shock. Interestingly, circulation of pandemic influenza A-H1N1 2009 in Managua was shifted such that it overlapped with the dengue epidemic. We hypothesize that prior influenza A H1N1 2009 infection may have modulated subsequent DENV infection, and initial results of an ongoing study suggest increased risk of shock among children with anti-H1N1-2009 antibodies. This study demonstrates that parameters other than serotype, viral genomic sequence, immune status, and sequence of serotypes can play a role in modulating dengue disease outcome.     

Genetic diversity of near genome-wide hepatitis C virus sequences during chronic infection: evidence for protein structural conservation over time

Infection with hepatitis C virus (HCV) is one of the leading causes of chronic hepatitis, liver cirrhosis and end-stage liver disease worldwide. The genetics of HCV infection in humans and the disease course of chronic hepatitis C are both remarkably variable. Although the response to interferon treatment is largely dependent on HCV genotypes, whether or not a relationship exists between HCV genome variability and clinical course of hepatitis C disease still remains unknown. To more thoroughly understand HCV genome evolution over time in association with disease course, near genome-wide HCV genomes present in 9 chronically infected participants over 83 total study years were sequenced. Overall, within HCV genomes, the number of synonymous substitutions per synonymous site (d(S)) significantly exceeded the number of non-synonymous substitutions per site (d(N)). Although both d(S) and d(N) significantly increased with duration of chronic infection, there was a highly significant decrease in d(N)/d(S) ratio in HCV genomes over time. These results indicate that purifying selection acted to conserve viral protein structure despite persistence of high level of nucleotide mutagenesis inherent to HCV replication. Based on liver biopsy fibrosis scores, HCV genomes from participants with advanced fibrosis had significantly greater d(S) values and lower d(N)/d(S) ratios compared to participants with mild liver disease. Over time, viral genomes from participants with mild disease had significantly greater annual changes in d(N), along with higher d(N)/d(S) ratios, compared to participants with advanced fibrosis. Yearly amino acid variations in the HCV p7, NS2, NS3 and NS5B genes were all significantly lower in participants with severe versus mild disease, suggesting possible pathogenic importance of protein structural conservation for these viral gene products.     

Chromium (VI) induced oxidative stress in Hapalosiphon fontinalis

Heavy metals in air, soil, and water are great threat to the environment. Effluents from paint, tannery, electroplating industries contaminate irrigation water, which in turn exhibit toxic response to many crops and microorganisms including cyanobacterial biofertilizers. In aquatic system Cr exist in many forms, whereas, Cr(VI) is most toxic. In the present study metabolic alteration were studied in a cyanobacterial biofertilizer (Hapalosiphon fontinalis) in response to chromium (VI) with special reference to oxidative stress. Maximum growth inhibition was observed at 0.5 mM Cr at 20th day. Lipid peroxidation as TBARS increased with the increase in chromium concentration and suggested free radical mediated toxicity. Elevated levels of β- carotene, astaxanthin, superoxide dismutase, catalase and ascorbate peroxidase indicated their role in survival strategy of the test organism.