Thiamine reduces tissue lead levels in rats: mechanism of interaction

Lead (Pb) toxicity has been a serious concern in industrialized societies because of its association with functional deficits in nervous, haematopoietic and renal systems. Several studies have shown beneficial effects of thiamine on Pb toxicity. It is speculated that Pb chelation by thiamine may be a possible mechanism. However, the exact nature of these interactions remained elusive. In the present study we have characterized the interaction of Pb with thiamine using UV–Vis as well as fluorescence spectroscopic methods and studied the effect of thiamine treatment on blood and tissue Pb levels during simultaneous or post-exposure to Pb in rat model. The spectroscopic studies revealed that Pb interacts with the pyrimidine ring of thiamine, leading to its solubilization at physiological pH. Further, thiamine reduced the Pb levels in blood, kidney and bone during both simultaneous and post-exposure Pb treatment. Interestingly, thiamine appears to prevent the accumulation of Pb in bone during simultaneous treatment. Together these results suggest that pyrimidine ring of thiamine mediates its interaction with Pb, leading to the prevention of its accumulation and/or increased clearance from tissues.     

Searching for the signal of competition in plant-mediated interactions among coexisting gall insects on broad-leaved paperbark

The central prediction of competition theory is that a reciprocal struggle for resources should manifest itself among coexisting species under conditions of increasing functional similarity (e.g. similar feeding niche), density and spatio-temporal overlap. We investigated whether the signal from such a struggle was evident in a community of phytophagous gall insects on Melaleuca quinquenervia meeting these conditions. Specifically, we examined plant-mediated interactions among three species galling vegetative tips with varying degrees of temporal overlap. The abundance of early gallers (Sphaerococcus ferrugineus Froggatt and Fergusonina turneri Taylor) did not influence resource availability for the late galler (Lophodiplosis indendata Gagné), suggesting the absence of temporally separated exploitative competition. However, the abundance of S. ferrugineus was positively correlated with the abundance of L. indentata, which suggests facilitation or similar responses to the prevailing conditions. Examination of the reciprocal impacts of the late galler on early gallers paradoxically revealed that though galling by L. indentata may be reducing the resource availability for early gallers, the abundance of L. indentata was positively influenced by the abundance of early gallers (an effect that is stronger for S. ferrugineus than F. turneri) suggesting facilitation. The strong influence of site on the interactions among the different cecidogenic species indicated that any role for competition/facilitation may be spatially constrained. We explore potential processes that may be driving the patterns that we detected and also the implications for the use of these species as biological control agents for M. quinquenervia.     

In vitro comparative cytotoxic assessment of pristine and carboxylic functionalized multiwalled carbon nanotubes on LN18 cells

Multiwalled carbon nanotubes (MWCNTs) have been used in biomedical applications due to their ability to enter the cells. Carboxylic functionalization of MWCNT (MWCNT-COOH) is used to mitigate the toxicity of MWCNTs. Our study focuses on comparing the toxicity of MWCNT and MWCNT-COOH on the neuronal cells, LN18. Concentrations of 5, 10, 20, and 40 µg ml⁻¹ were used for the study, and cytotoxicity was determined at 0, 1, 3, 6, 12, 24, and 48 h of incubation. Cell viability was assessed by Trypan Blue, MTT, and Live dead cell assays, and the oxidative stress produced was determined by reactive oxygen species (ROS) and Lipid peroxidation assays. MWCNT-COOH showed higher cell viability than MWCNT for 20 and 40 µg ml⁻¹ at 24 and 48 h. This was also visually observed in the live dead cell imaging. However, at 48 h, the morphology of the cells appeared more stretched for all the concentrations of MWCNT and MWCNT-COOH in comparison to the control. A significant amount of ROS production can also be observed at the same concentration and time. Viability and oxidative stress results together revealed that MWCNT-COOH is less toxic when compared to MWCNT at longer incubation periods and higher concentrations. However, otherwise, the effect of both are comparable. A concentration of 5–10 µg ml⁻¹ is ideal while using MWCNT and MWCNT-COOH as the toxicity is negligible. These findings can further be extended to various functionalizations of MWCNT for wider applications.     

Response of an invasive liana to simulated herbivory: implications for its biological control

Pre-release evaluation of the efficacy of biological control agents is often not possible in the case of many invasive species targeted for biocontrol. In such circumstances simulating herbivory could yield significant insights into plant response to damage, thereby improving the efficiency of agent prioritisation, increasing the chances of regulating the performance of invasive plants through herbivory and minimising potential risks posed by release of multiple herbivores. We adopted this approach to understand the weaknesses herbivores could exploit, to manage the invasive liana, Macfadyena unguis-cati. We simulated herbivory by damaging the leaves, stem, root and tuber of the plant, in isolation and in combination. We also applied these treatments at multiple frequencies. Plant response in terms of biomass allocation showed that at least two severe defoliation treatments were required to diminish this liana's climbing habit and reduce its allocation to belowground tuber reserves. Belowground damage appears to have negligible effect on the plant's biomass production and tuber damage appears to trigger a compensatory response. Plant response to combinations of different types of damage did not differ significantly to that from leaf damage. This suggests that specialist herbivores in the leaf-feeding guild capable of removing over 50% of the leaf tissue may be desirable in the biological control of this invasive species.     

A critical review on antiviral peptides derived from viral glycoproteins and host receptors to decoy herpes simplex virus

The health of the human population has been continuously challenged by viral infections. Herpes simplex virus (HSV) is one of the common causes of illness and can lead to death in immunocompromised patients. Existing anti-HSV therapies are not completely successful in eliminating the infection due to anti-viral drug resistance, ineffectiveness against the latent virus and high toxicity over prolonged use. There is a need to update our knowledge of the current challenges faced in anti-HSV therapeutics and realize the necessity of developing alternative treatment approaches. Protein therapeutics are now being explored as a novel approach due to their high specificity and low toxicity. This review highlights the significance of HSV viral glycoproteins and host receptors in the pathogenesis of HSV infection. Proteins or peptides derived from HSV glycoproteins gC, gB, gD, gH and host cell receptors (HSPG, nectin and HVEM) that act as decoys to inhibit HSV attachment, entry, or fusion have been discussed. Few researchers have tried to improve the efficacy and stability of the identified peptides by modifying them using a peptidomimetic approach. With these efforts, we think developing an alternative treatment option for immunocompromised patients and drug-resistant organisms is not far off.     

Stand dynamics and spatial patterns across varying sites in the invasive Lantana camara L. (Verbenaceae)

As with many invasive plant species, little is known of the population spatial patterns and stand dynamics of Lantana camara L. (Verbenaceae)??a thicket-forming weed of worldwide significance in managed and conservation lands, including coastal and inland habitats of Eastern Australia. Consequently, we mapped and followed annually for 3?years the demographic fate of more than 2000 Lantana individuals at sites with four land-uses (hoop pine plantation, cattle farm, and two eucalyptus forests with occasional grazing and periodic burning regime, respectively) in Queensland, SE Australia. Populations exhibited plant size distributions that were continuous (i.e., of L or symmetric type) and unimodal, except the farm population where bimodality was observed. Newly established plants could be reproductive within one growing season at ~50?cm in height, especially where environmental resources were not limiting. Density had an appreciable effect on the weed??s reproductive capacity and growth, but not on survival. Established and newly recruited individuals were aggregated but the degree of aggregation decreased with plant size. However, in the sites that had experienced burning or mechanical clearing, Lantana seedling/juvenile recruitment assumed negative association (spatial displacement) in relation to established individuals. The findings of this study agree with the notion that ecological processes often leave characteristic spatial signatures, which if interpreted using appropriate hypotheses can help to ascertain factors responsible for the observed spatial patterns and stand dynamics.     

Zirconia-Cu(I) stabilized copper oxide mesoporous nano-catalyst: Synthesis and DNA reactivity of 1,2,4-oxadiazole-quinolinepeptidomimetics-based metal(II) complexes

Abstract

Contemporary research reveals an undemanding protocol for the catalytic synthesis of 1,2,4-oxadiazole-quinolinepeptide in the incidence of a cost-effective and reusable mesoporous ZrO₂-supported Cu₂O (Cu₂ZrO₃) catalyst. This paper depicts a unique system for peptide bond synthesis staying away from toxic solvents and reactants. The catalyst was reused for four cycles without noteworthy loss in the activity, and the catalyst was genuinely heterogeneous. The method followed a simple workup procedure, and no column chromatography was needed. Further, the synthesized 1,2,4-oxadiazole-quinolinepeptide ligand (L), and its complexes of type, [FeLCl₂] and [CuL]Cl₂ were synthesized and characterized by spectral and analytical techniques. An octahedral geometry has been projected for Fe(II) complexes, while the Cu(II) complex exhibits a square planar geometry. The binding properties of the complexes with CT-DNA were studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. The photo-induced cleavage studies revealed that the complexes possess photonuclease activity against pUC19 DNA under UV–visible irradiation.     

Radioprotective role of uric acid: evidence from studies in Drosophila and human dermal fibroblast cells

Molecular Biology Reports - Exposure to ionizing radiation (IR) is a common phenomenon during medical diagnosis and treatment. IRs are deleterious because cellular exposure to IR can cause a series...