Role In Scavenging Research Articles

Hypoalbuminemia: Pathogenesis and Clinical Significance.

Hypoalbuminemia is associated with inflammation. Despite being addressed repeatedly in the literature, there is still confusion regarding its pathogenesis and clinical significance. Inflammation increases capillary permeability and escape of serum albumin, leading to expansion of interstitial space and increasing the distribution volume of albumin. The half‐life of albumin has been shown to shorten, decreasing total albumin mass. These 2 factors lead to hypoalbuminemia despite increased fractional synthesis rates in plasma. Hypoalbuminemia, therefore, results from and reflects the inflammatory state, which interferes with adequate responses to events like surgery or chemotherapy, and is associated with poor quality of life and reduced longevity. Increasing or decreasing serum albumin levels are adequate indicators, respectively, of improvement or deterioration of the clinical state. In the interstitium, albumin acts as the main extracellular scavenger, antioxidative agent, and as supplier of amino acids for cell and matrix synthesis. Albumin infusion has not been shown to diminish fluid requirements, infection rates, and mortality in the intensive care unit, which may imply that there is no body deficit or that the quality of albumin “from the shelf” is unsuitable to play scavenging and antioxidative roles. Management of hypoalbuminaemia should be based on correcting the causes of ongoing inflammation rather than infusion of albumin. After the age of 30 years, muscle mass and function slowly decrease, but this loss is accelerated by comorbidity and associated with decreasing serum albumin levels. Nutrition support cannot fully prevent, but slows down, this chain of events, especially when combined with physical exercise.

Nymphaea pubescens Induces Apoptosis, Suppresses Cellular Oxidants-Related Cell Invasion in B16 Melanoma Cells

Background: Nymphaea spp., Thai water lilies are aquatic plants. They contain phenolic pigments that play a major role in free radical scavenging. Melanoma is strong aggressive skin cancer-associated with oxidative stress. This study, to determine the effect of Nymphaea spp. extracts on cell apoptosis, cellular migration and invasion through the role of cellular oxidants in B16 melanoma cells. Methods: Free radical scavenging activity and total phenolic were investigated by 1, 1-diphenyl-2 picrylhydrazyl (DPPH) and Ferric reducing anti-oxidant power (FRAP) methods and Folin-Denis test, respectively. Cytotoxic were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Cell apoptosis was confirmed by flow cytometry. Cellular oxidants, cellular migration and invasion were determined with 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA), wound healing and Boyden chamber assay, respectively. Results: Nymphaea pubescens showed higher capacity of scavenging free radical activity than Nymphaea stellate and also related phenolic content. Nymphaea pubescens extract was toxic to B16 melanoma cells. High concentrations cell apoptosis was induced. Contrastingly, low concentrations showed a decrease in cellular oxidants associated with the suppression of cancer cell progression. In B16 melanoma cell, Nymphaea pubescens extract was able to inhibit B16 melanoma cell migration and invasion through the low doses. Interestingly, the high doses of extract showed a potential of cytotoxicity to induce melanoma cell death. At the low doses, Nymphaea pubescens extract might suppress melanoma cells progression by interfering with both cellular migration and invasion capacity. Conclusion: Hence, Nymphaea pubescens extract induced cellular apoptosis and it also suppressed cancer cell progression by reducing oxidative stress in B16 melanoma cells.

An army of one: predaceous diving beetle life history stages affect interactions with shared mosquito prey

Predators with complex life cycles often differ in their morphology, behavior, and trophic position across their ontogeny, and may thus have variable effects on shared prey. We used the predaceous diving beetle Laccophilus fasciatus rufus as our predator, whose larvae and adults often co-occur in freshwater lentic systems. As a shared prey we used early and late instar Culex quinquefasciatus, a common wetland mosquito. We found that single adult predators were more likely to consume late instar prey compared to juvenile predators, who ate early and late instar prey equally. A mixture of juvenile and adult predator stages led to higher consumption of prey when compared to either predator type alone. Adult dytiscids consumed three times as many dead prey compared to living ones, thus implying a role in scavenging for this life-history stage. Our work highlights that predators with complex life-history stages may affect shared prey in complicated and unpredictable ways.

Redox Regulation of Starch Metabolism

Metabolism of starch is a major biological integrator of plant growth supporting nocturnal energy dynamics by transitory starch degradation as well as periods of dormancy, re-growth, and reproduction by utilization of storage starch. Especially, the extraordinarily well-tuned and coordinated rate of transient starch biosynthesis and degradation suggests the presence of very sophisticated regulatory mechanisms. Together with the circadian clock, land plants (being autotrophic and sessile organisms) need to monitor, sense, and recognize the photosynthetic rate, soil mineral availability as well as various abiotic and biotic stress factors. Currently it is widely accepted that post-translational modifications are the main way by which the diel periodic activity of enzymes of transient starch metabolism are regulated. Among these mechanisms, thiol-based redox regulation is suggested to be of fundamental importance and in chloroplasts, thioredoxins (Trx) are tightly linked up to photosynthesis and mediate light/dark regulation of metabolism. Also, light independent NADP-thioredoxin reductase C (NTRC) plays a major role in reactive oxygen species scavenging. Moreover, Trx and NTRC systems are interconnected at several levels and strongly influence each other. Most enzymes involved in starch metabolism are demonstrated to be redox-sensitive in vitro. However, to what extent their redox sensitivity is physiologically relevant in synchronizing starch metabolism with photosynthesis, heterotrophic energy demands, and oxidative protection is still unclear. For example, many hydrolases are activated under reducing (light) conditions and the strict separation between light and dark metabolic pathways is now challenged by data suggesting degradation of starch during the light period.

The Effect of Cadmium on Oxidative Stress in Beta vulgaris

Abstract As a heavy metal, cadmium has strongly toxic effects on plants and can induce oxidative stress. It is absorbed by the roots and transported to the stems and leaves. The aim of the study was to evaluate the effect of various concentrations of cadmium on the metabolic activity of Beta vulgaris and assess the dependence of these processes on the content of metal in the plants. To demonstrate the effect of cadmium on metabolism, protein and photosynthetic pigment content, lipid peroxidation, and the activity of enzymes specific for oxidative stress in roots and shoots were measured. Seeds of B. vulgaris were treated with different concentrations of Cd supplied via a CdCl2 solution: 0 (control), 200, 300 and 400 mg/dm3. Results of the present study revealed increased GPOX activity as cadmium concentration rose, while SOD activity was stimulated by a low Cd concentration (200 mg/dm3) and reduced by high levels of Cd. Based on the present findings, it can be concluded that GPOX in B. vulgaris played a more important role in ROS scavenging than SOD did and was able to reduce the level of lipid peroxidation in plants. Cadmium, in the concentration range used, did not show any significant effect on protein or photosynthetic pigment content.

Enhancement of ethanol production in very high gravity fermentation by reducing fermentation-induced oxidative stress in Saccharomyces cerevisiae

During fermentation, yeast cells encounter a number of stresses, including hyperosmolarity, high ethanol concentration, and high temperature. Previous deletome analysis in the yeast Saccharomyces cerevisiae has revealed that SOD1 gene encoding cytosolic Cu/Zn-superoxide dismutase (SOD), a major antioxidant enzyme, was required for tolerances to not only oxidative stress but also other stresses present during fermentation such as osmotic, ethanol, and heat stresses. It is therefore possible that these fermentation-associated stresses may also induce endogenous oxidative stress. In this study, we show that osmotic, ethanol, and heat stresses promoted generation of intracellular reactive oxygen species (ROS) such as superoxide anion in the cytosol through a mitochondria-independent mechanism. Consistent with this finding, cytosolic Cu/Zn-SOD, but not mitochondrial Mn-SOD, was required for protection against oxidative stress induced by these fermentation-associated stresses. Furthermore, supplementation of ROS scavengers such as N-acetyl-L-cysteine (NAC) alleviated oxidative stress induced during very high gravity (VHG) fermentation and enhanced fermentation performance at both normal and high temperatures. In addition, NAC also plays an important role in maintaining the Cu/Zn-SOD activity during VHG fermentation. These findings suggest the potential role of ROS scavengers for application in industrial-scale VHG ethanol fermentation.

Abstract B097: NRF2 antioxidant signaling mediates the ability of PIM protein kinases to induce resistance of prostate cancer to PI3K inhibitor therapy

Abstract Aberrant activation of the PI3K pathway leading to increases in AKT activity is seen in many prostate cancer patients refractory to androgen blockade therapy. A number of small-molecule inhibitors of PI3K, including BKM120 (Novartis), have entered clinical trials. As with PI3K-AKT activation, highly expressed Pim kinase has been shown to drive the growth of prostate cancer. Recent studies have demonstrated that Pim kinase plays a critical role in promoting resistance of breast cancer to PI3K inhibition. Similarly, when the Pim-1 protein kinase is overexpressed, prostate cancer cell lines become resistant to PI3K inhibitor. In both tissue culture and animal models, the combination of a Pim inhibitor, PIM447, and BKM120 acted synergistically in blocking the survival and growth of prostate cancer cells. We therefore investigated the biochemical mechanism by which Pim-1 mediates cell resistance to the PI3K inhibitor. Previously, we have demonstrated that knockout of Pim kinases led to accumulation of reactive oxygen species (ROS) accompanied by a lower level of expression of ROS scavengers. To explore whether Pim-1 overexpression reverses this phenotype in prostate epithelial cancer, using lentiviral transduction, we expressed Pim-1 in mouse prostate epithelial cancer cells derived from spontaneous prostate adenocarcinomas that arose in a mouse model in which Tp53 and Rb1 are deleted in prostate epithelium. Pim-1 overexpression promoted anchorage-independent growth and formation of mouse prostate epithelial tumors in vivo. Gene expression arrays demonstrated that Pim-1 induced an Nrf2 antioxidant response element gene signature, including increases in Heme oxygenase-1 (Hmox1), NAD(P)H quinone oxidoreductase 1 (Nqo1), and glutathione S-transferase kappa1 (Gstk1) genes. Similarly, overexpression of Pim-1 in human prostate cancer LNCaP cells results in increased expression of Nrf2 and Hmox1 protein. As expected, depletion of Nrf2 with shRNA prevented Pim-1-mediated increases in Hmox1 expression, indicating that Nrf2 activation is required for the Pim-1 induction of ROS scavengers. In line with this result, in Pim-1 overexpressing cell lines knockdown of either Hmox1 or Nrf2 restored sensitivity to BKM120 treatment. A vital role of ROS scavengers in mediating the resistance to BKM120 was further confirmed by the treatment of cells and xenografted tumors with buthionine sulfoximine (inhibitor of glutathione synthesis), which resensitized the Pim-1 overexpressing cells to BKM120 via ROS induction. Our data further demonstrated that Pim-1 overexpression decreases the ubiquitination of Nrf2 protein, thus preventing its degradation, and increasing its half-life. Conversely, inhibition of Pim kinase promoted Nrf2 ubiquitination and proteasomal degradation. Taken together, our results show that the increased expression of Pim kinases in prostate cancer blocks therapeutic efficacy of PI3K inhibitor by inducing Nrf2 and antioxidant scavengers that inhibit the induction of ROS. Citation Format: Jin H. Song, Libia A. Leuvano, Neha Singh, Andrew S. Kraft. NRF2 antioxidant signaling mediates the ability of PIM protein kinases to induce resistance of prostate cancer to PI3K inhibitor therapy [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B097.

Proteomic discovery of H2O2 response in roots and functional characterization of PutGLP gene from alkaligrass.

Hydrogen peroxide-responsive pathways in roots of alkaligrass analyzed by proteomic studies and PutGLP enhance the plant tolerance to saline-, alkali- and cadmium-induced oxidative stresses. Oxidative stress adaptation is critical for plants in response to various stress environments. The halophyte alkaligrass (Puccinellia tenuiflora) is an outstanding pasture with strong tolerance to salt and alkali stresses. In this study, iTRAQ- and 2DE-based proteomics approaches, as well as qRT-PCR and molecular genetics, were employed to investigate H2O2-responsive mechanisms in alkaligrass roots. The evaluation of membrane integrity and reactive oxygen species (ROS)-scavenging systems, as well as abundance patterns of H2O2-responsive proteins/genes indicated that Ca2+-mediated kinase signaling pathways, ROS homeostasis, osmotic modulation, and transcriptional regulation were pivotal for oxidative adaptation in alkaligrass roots. Overexpressing a P. tenuiflora germin-like protein (PutGLP) gene in Arabidopsis seedlings revealed that the apoplastic PutGLP with activities of oxalate oxidase and superoxide dismutase was predominantly expressed in roots and played important roles in ROS scavenging in response to salinity-, alkali-, and CdCl2-induced oxidative stresses. The results provide insights into the fine-tuned redox-responsive networks in halophyte roots.

Purine and pyrimidine salvage pathway in thermophiles: a valuable source of biocatalysts for the industrial production of nucleic acid derivatives.

Due to their similarity to natural counterparts, nucleic acid derivatives (nucleobases, nucleosides, and nucleotides, among others) are interesting molecules for pharmaceutical, biomedical, or food industries. For this reason, there is increasing worldwide demand for the development of efficient synthetic processes for these compounds. Chemical synthetic methodologies require numerous protection-deprotection steps and often lead to the presence of undesirable by-products or enantiomeric mixtures. These methods also require harsh operating conditions, such as the use of organic solvents and hazard reagents. Conversely, enzymatic production by whole cells or enzymes improves regio-, stereo-, and enantioselectivity and provides an eco-friendly alternative. Because of their essential role in purine and pyrimidine scavenging, enzymes from purine and pyrimidine salvage pathways are valuable candidates for the synthesis of many different nucleic acid components. In recent years, many different enzymes from these routes, such as nucleoside phosphorylases, nucleoside kinases, 2'-deoxyribosyltransferases, phosphoribosyl transferases, or deaminases, have been successfully employed as biocatalysts in the production of nucleobase, nucleoside, or nucleotide analogs. Due to their great activity and stability at extremely high temperatures, the use of enzymes from thermophiles in industrial biocatalysis is gaining momentum. Thermophilic enzymes not only display unique characteristics such as temperature, chemical, and pH stability but also provide many different advantages from an industrial perspective. This mini-review aims to cover the most representative enzymatic approaches for the synthesis of nucleic acid derivatives. In this regard, we provide detailed comments about enzymes involved in crucial steps of purine and pyrimidine salvage pathways in thermophiles, as well as their biological role, biochemical characterization, active site mechanism, and substrate specificity. In addition, the most interesting synthetic examples reported in the literature are also included.

Chlorotrimethylsilane-promoted synthesis of 1,2,4-triazolopyrimidines from 3,5-diamino-1,2,4-triazoles and pentane-2,4-diones

An efficient synthesis of 2-amino-1-R-[1,2,4]triazolo[1,5-a]-pyrimidinium or 3-amino-2-R-[1,2,4]triazolo[4,3-a]pyrimidi- nium chloride derivatives by heterocyclization of 3,5-diamino-1-R-1,2,4-triazoles (R = Alk or Ar) with pentane-2,4-diones was developed. The process is promoted by chlorotrimethyl- silane which plays the dual role of carbonyl-activating agent and water scavenger.

In vitro assessment of antimicrobial and genotoxic effect of metallosurfactant based nickel hydroxide nanoparticles against Escherichia coli and its genomic DNA.

In the present study, we have synthesized nickel hydroxide nanosuspensions (Ns) using microemulsion technique. This approach is eco-friendly and makes use of Tween 80 (a non-ionic biocompatible surfactant) and newly synthesized metallosurfactants for the formation of uniform nanoparticles in the form of nanosuspensions (Ns). The nickel hydroxide Ns's were derived from three different metallosurfactants i.e. NiCTAC (Bishexadecyltrimethylammonium nickel tetrachloride), NiDDA (Bisdodecylamine nickel dichloride) and NiHEXA (bishexadecylamine nickel dichloride). Three different nickel-based metallosurfactants were synthesized and characterized using various methods such as CHN, 1HNMR, and FTIR. Fabrication of nanosuspension was confirmed using different characterization methods such as Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), pH and Zeta potential. These particles were further investigated for their genotoxic and cytotoxic effects on gram-negative bacteria, Escherichia coli (E. coli). Effect of nanosuspensions on E. coli was confirmed using colony forming unit count, agar well diffusion, and gram staining method. Through colony forming unit count method, nanosuspensions influence on the colony-forming capacity of E. coli cells was confirmed. Agar well diffusion method provides the estimation of antimicrobial activity, and the largest inhibition zone was observed for NiCTAC Ns and smallest for NiHEXA Ns which is related to maximum and minimum bactericidal properties of Ns, respectively. The interaction behavior of bacterial DNA with Ni nanosuspension was analyzed using agarose gel electrophoresis and circular dichroism. Along with, the role of different chemical scavengers was also evaluated in DNA damage using gel electrophoresis. Furthermore, the antioxidant activity of Ni nanosuspension was also confirmed using DPPH assay.

Spores and soil from six sides: interdisciplinarity and the environmental biology of anthrax (Bacillus anthracis).

Environmentally transmitted diseases are comparatively poorly understood and managed, and their ecology is particularly understudied. Here we identify challenges of studying environmental transmission and persistence with a six-sided interdisciplinary review of the biology of anthrax (Bacillus anthracis). Anthrax is a zoonotic disease capable of maintaining infectious spore banks in soil for decades (or even potentially centuries), and the mechanisms of its environmental persistence have been the topic of significant research and controversy. Where anthrax is endemic, it plays an important ecological role, shaping the dynamics of entire herbivore communities. The complex eco-epidemiology of anthrax, and the mysterious biology of Bacillus anthracis during its environmental stage, have necessitated an interdisciplinary approach to pathogen research. Here, we illustrate different disciplinary perspectives through key advances made by researchers working in Etosha National Park, a long-term ecological research site in Namibia that has exemplified the complexities of the enzootic process of anthrax over decades of surveillance. In Etosha, the role of scavengers and alternative routes (waterborne transmission and flies) has proved unimportant relative to the long-term persistence of anthrax spores in soil and their infection of herbivore hosts. Carcass deposition facilitates green-ups of vegetation to attract herbivores, potentially facilitated by the role of anthrax spores in the rhizosphere. The underlying seasonal pattern of vegetation, and herbivores' immune and behavioural responses to anthrax risk, interact to produce regular 'anthrax seasons' that appear to be a stable feature of the Etosha ecosystem. Through the lens of microbiologists, geneticists, immunologists, ecologists, epidemiologists, and clinicians, we discuss how anthrax dynamics are shaped at the smallest scale by population genetics and interactions within the bacterial communities up to the broadest scales of ecosystem structure. We illustrate the benefits and challenges of this interdisciplinary approach to disease ecology, and suggest ways anthrax might offer insights into the biology of other important pathogens. Bacillus anthracis, and the more recently emerged Bacillus cereus biovar anthracis, share key features with other environmentally transmitted pathogens, including several zoonoses and panzootics of special interest for global health and conservation efforts. Understanding the dynamics of anthrax, and developing interdisciplinary research programs that explore environmental persistence, is a critical step forward for understanding these emerging threats.

MoYvh1 subverts rice defense through functions of ribosomal protein MoMrt4 in Magnaporthe oryzae.

The accumulation of the reactive oxygen species (ROS) in rice is important in its interaction with the rice blast fungus Magnaporthe oryzae during which the pathogen scavenges ROS through the production of extracellular enzymes that promote blast. We previously characterized the MoYvh1 protein phosphatase from M. oryzae that plays a role in scavenging of ROS. To understand the underlying mechanism, we found that MoYvh1 is translocated into the nucleus following oxidative stress and that this translocation is dependent on MoSsb1 and MoSsz1 that are homologous to heat-shock protein 70 (Hsp70) proteins. In addition, we established a link between MoYvh1 and MoMrt4, a ribosome maturation factor homolog whose function also involves shuttling between the cytoplasm and the nucleus. Moreover, we found that MoYvh1 regulates the production of extracellular proteins that modulate rice-immunity. Taking together, our evidence suggests that functions of MoYvh1 in regulating ROS scavenging require its nucleocytoplasmic shuttling and the partner proteins MoSsb1 and MoSsz1, as well as MoMrt4. Our findings provide novel insights into the mechanism by which M. oryzae responds to and subverts host immunity through the regulation of ribosome biogenesis and protein biosynthesis.

1377 Decoding frontal fibrosing alopecia and lichen planopilaris: Macrophages hold the key?

Frontal fibrosing alopecia (FFA) and Lichen planopilaris are inflammatory hair discorders leading to hair follicle (HF) destruction and scarring. Traditionally FFA has been regarded as a variant of lichen planopilaris (LPP) based on histological features, however, distinct phenotypic differences argue against this. So far clinicians and scientists have failed to describe the differences between each pathology. As macrophages are known scavengars of the immune system, having a role in programmed organ deletion and also are implicated in human hair cycle cotrol, they may hold the key. Therefore in this strudy we have investigated the macrophage populations utilising CD68 staining to investigate their role in LPP and FFA pathogenesis. Results showed that CD68 was expressed in both LPP and FFA compared with controls with staining being prominent in partially destroyed HFs. Comparing LPP to FFA, there was a significantly increased number of CD68+ cells in LPP HFs compared with both FFA and control samples suggesting they may have a different role in LPP when compared with FFA. This was found in both in the peri-follicular and the inter-follicular mesenchye. That the macrophage population was more prominent in LPP suggests they may have a more substantial role in the pathogenesis of LPP than FFA. Next it is essential to characterize the polarization of macrophages and the role these immune cells have in pathogenesis, i.e. a scavenger role or secretory cells producing cytokines such and IFN leading to IP loss and stem cell destruction. Our preliminary study provides the first evidence suggesting a subtle yet important difference in the pathogenesis of LPP and FFA. By understnding the differences between each condition we can aim to devise better targetted treatment strategies to prevent and restore hair loss leading to better clinical outcomes.

Fipronil recognition by the FA1 site of human serum albumin.

Fipronil is a broad-spectrum pesticide widely used in agriculture, horticulture, and forestry. Because fipronil can cause a variety of toxic effects in animals and humans, its use is authorized as a pesticide in veterinary medicinal products for pets, but not for the treatment of livestock animals whose products are intended for consumption. Recently, however, the presence of fipronil residues has been detected in the eggs and meat of layer hens from farms located in different European countries. Given the relevance of fipronil toxicity for human health, it is important to gain information concerning its fate in the human body, including its binding mode to human serum albumin (HSA), the most abundant protein in plasma. Here, the inhibition of heme-Fe(III) binding to the fatty acid site 1 (FA1) of HSA by fipronil is reported. Docking simulations support functional data, indicating that the FA1 site is the preferential cleft for fipronil recognition by HSA. The affinity of fipronil for HSA (Kf =1.9×10-6 M, at pH 7.3, and 20.0°C) may be relevant in vivo. Indeed, HSA could play a pivotal role in fipronil transport and scavenging, thus reducing the pesticide-free plasmatic levels, with consequent reduced systemic toxicity. In turn, fipronil binding to the FA1 site of HSA could impair the recognition of endogenous and exogenous molecules.

A new role for mast cells as scavengers for clearance of erythrocytes damaged due to oxidative stress

Anemia, inflammation, and oxidative stress are interconnected. Erythrocytes are continuously exposed to oxidative stress, normally and during inflammatory diseases. Systemic mastocytosis and genetic depletion of mast cells affect anemia. In the present study, a direct role for mast cells in clearance of erythrocytes was explored. We show, for the first time, direct phagocytosis of opsonized as well as oxidatively damaged erythrocytes in vitro by mast cell lines, bone marrow derived mast cells (BMMCs) and in vivo by murine peritoneal mast cells. Also, activated mast cells, as may be present in inflammatory conditions, showed a significantly higher uptake of oxidatively damaged erythrocytes than resting mast cells. This suggests the involvement of mast cells in erythrocyte clearance during oxidative stress or inflammatory disorders. Partial inhibition of phagocytosis by various inhibitors indicated that this process may be controlled by several pathways. Our study provides important evidence for a scavenging role for mast cells in anemia due to inflammation and oxidative stress.

Radical scavenging activity of sulfated Bupleurum chinense polysaccharides and their effects against oxidative stress-induced senescence

In this study, BCPS-1, a polysaccharide previously isolated and characterized from Bupleurum chinense was chemically modified to yield two sulfated derivatives, which we designated as S-BCP1-4 and S-BCP1-8. The physicochemical properties of these sulfated derivatives were then determined by high performance liquid chromatography (HPLC), Fourier transform infrared spectrometry (FT-IR), and gas chromatography (GC), and then compared with those of BCPS-1. Furthermore, the antioxidant activities of all three polysaccharides were also evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay, superoxide radical assay and hydroxyl radical assay, while their effects against H2O2-induced cellular senescence were determined using senescence-associated β-galactosidase (SA-β-gal) staining, cell cycle assay and immunoblotting in H2O2-induced mouse lung endothelial cells (MLECs). Compared to BCPS-1, S-BCP1-4 and S-BCP1-8 exhibited remarkable antioxidant effect, and in a concentration-dependent manner. They also provided stronger protection against H2O2-induced cellular senescence in MLECs. These results indicated that the sulfate group in the modified B. chinense polysaccharides might play an important role in radical scavenging and resistance to H2O2-induced senescence. These sulfated polysaccharides could be considered as novel pharmaceutical products with potential antioxidant and anti-senescence effects.

Biochemical, Structural and Physiological Characteristics of Vacuolar H+-Pyrophosphatase.

Proton-translocating inorganic pyrophosphatase (H+-PPase) actively translocates protons across membranes coupled with the hydrolysis of inorganic pyrophosphate (PPi). H+-PPase, which is composed of a single protein and uses a simple compound as a substrate, has been recognized as a new type of ion pump in addition to the P-, F- and V-type ion-translocating ATPases. H+- and Na+-PPases are distributed in various organisms including plants, parasitic protozoa, Archaebacteria and bacteria, but are not present in animals or yeast. Vacuolar H+-PPase has dual functions in plant cells: hydrolysis of cytosolic PPi to maintain the levels of PPi, and translocation of protons into vacuoles to maintain the acidity of the vacuolar lumen. Acidification performed with the vacuolar-type H+-ATPase and H+-PPase is essential to maintain acidic conditions, which are necessary for vacuolar hydrolytic enzymes and for supplying energy to secondary active transporters. Recent studies using loss-of-function mutant lines of H+-PPase and complementation lines with soluble PPases have emphasized the physiological importance of the scavenging role of PPi. An overview of the main features of H+-PPases present in the vacuolar membrane is provided in terms of tissue distribution in plants, intracellular localization, structure-function relationship, biochemical potential as a proton pump and functional stability.

A biodiversity survey of scavenging amphipods in a proposed marine protected area: the Filchner area in the Weddell Sea, Antarctica

An integrative inventory of the amphipod scavenging fauna (Lysianassoidea), combining morphological identifications with DNA barcoding, is provided here for the Filchner area situated in the south-eastern Weddell Sea. Over 4400 lysianassoids were investigated for species richness and relative abundances, covering 20 different stations and using different sampling devices, including the southernmost baited traps deployed so far (76°S). High species richness was observed: 29 morphospecies of which 5 were new to science. Molecular species delimitation methods were carried out with 109 cytochrome c oxidase I gene (COI) sequences obtained during this study as well as sequences from specimens sampled in other Antarctic regions. These distance-based analyses (trees and the Automatic Barcode Gap Discovery method) indicated the presence of 42 lineages; for 4 species, several (cryptic) lineages were found. More than 96% of the lysianassoids collected with baited traps belonged to the species Orchomenella pinguides s. l. The diversity of the amphipod scavenger guild in this ice-bound ecosystem of the Weddell Sea is discussed in the light of bottom–up selective forces. In this southernmost part of the Weddell Sea, harbouring spawning and nursery grounds for silverfish and icefishes, abundant fish and mammalian food falls are likely to represent the major food for scavengers. Finally, the importance of biodiversity surveys in the context of the establishment of a marine protected area in this region (Weddell Sea MPA) is highlighted and how future studies can contribute to a better understanding the ecological role of scavengers in this system is discussed.

Improving photoelectrochemical reduction of Cr(VI) ions by building α-Fe2O3/TiO2 electrode.

Photoelectrochemical process is an environmentally friendly technology and has a wide application in the control of environmental pollutants. Efficient nanophotocatalysts responsive to visible light are still highly attractive. In this work, α-Fe2O3/TiO2 were grown on fluorine doped tin oxide (FTO) substrates by hydrothermal method for photoelectrochemical reduction of Cr(VI). Compared with the separate α-Fe2O3 and TiO2 electrodes, the composite α-Fe2O3/TiO2 electrodes show higher photocurrent density. Under visible light irradiation, 100% removal efficiency of Cr(VI) was obtained after 40min treatment. The composite α-Fe2O3/TiO2 electrodes showed an enhanced absorbance in visible light region and had good stability to photoelectrochemical reduction of Cr(VI). The role of hole scavengers (citric acid and oxalic acid) and pH values was systematically investigated. This novel intensification approach provides new insight on the application of photoelectrochemical reduction in environmental remediation.