d-β-Hydroxybutyrate inhibited the apoptosis of PC12 cells induced by H2O2 via inhibiting oxidative stress

Oxidative stress has an important role in neurodegenerative diseases and cerebral ischemic injury. It is reported that d-β-hydroxybutyrate (DβHB), the major component of ketone bodies, is neuroprotective in recent studies. Therefore, in the present work the neuroprotective effects of DβHB on H₂O₂-induced apoptosis mediated by oxidative stress was investigated. PC12 cells were exposed to H₂O₂ with different concentrations of H₂O₂ for different times after DβHB pretreatment. MTT assay, apoptotic rates, intracellular reactive oxygen species (ROS) level, GSH content, mitochondrial membrane potential (MMP) and caspase-3 activity were determined. The results showed that DβHB inhibited the decrease of cell viability induced by H₂O₂ in PC12 cells. DβHB decreased the apoptotic rates induced by H₂O₂. The changes of intracellular ROS, GSH, MMP and caspase-3 activity due to H₂O₂ exposure were partially reversed in PC12 cells. So DβHB inhibited the apoptosis of PC12 cells induced by H₂O₂ via inhibiting oxidative stress.     

Effects of the Oral Administration of K<Subscript>2</Subscript>Cr<Subscript>2</Subscript>O<Subscript>7</Subscript> and Na<Subscript>2</Subscript>SeO<Subscript>3</Subscript> on Ca,Mg, Mn,Fe, Cu,and Zn Contents in the Heart,Liver, Spleen,and Kidney of Chickens

This study aimed to investigate the effects of selenium on the ion profiles in the heart, liver, spleen, and kidney through the oral administration of hexavalent chromium. Approximately 22.14 mg/kg b.w. K₂Cr₂O₇ was added to water to establish a chronic poisoning model. Different selenium levels (0.00, 0.31, 0.63, 1.25, 2.50, and 5.00 mg Na₂SeO₃/kg b.w.) around the safe dose were administered to the experimental group model. Ca, Mg, Mn, Fe, Cu, and Zn were detected in the organs through flame atomic absorption spectrometry after these organs were exposed to K₂Cr₂O₇ and Na₂SeO₃ for 14, 28, and 42 days. Results showed that these elements exhibited various changes. Ca contents declined in the heart, liver, and spleen. Ca contents also decreased on the 28th day and increased on the 42nd day in the kidney. Mn contents declined in the heart and spleen but increased in the kidney. Mn contents also decreased on the 28th day and increased on the 42nd day in the liver. Cu contents declined in the heart and spleen. Cu contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Zn contents declined in the heart and spleen. Zn contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Fe contents decreased in the heart and liver. Fe contents increased on the 28th day and decreased on the 42nd day in the spleen and kidney. Mg contents did not significantly change in these organs. Appropriate selenium contents enhanced Mn and Zn contents, which were declined by chromium. Conversely, appropriate selenium contents reduced Ca, Fe, and Cu contents, which were increased by chromium. In conclusion, the exposure of chickens to K₂Cr₂O₇ induced changes in different trace elements, and Na₂SeO₃ supplementation could alleviate this condition.     

Characterizing effects of excess copper levels in a human astrocytic cell line with focus on oxidative stress markers

BackgroundBeing an essential trace element, copper is involved in diverse physiological processes. However, excess levels might lead to adverse effects. Disrupted copper homeostasis, particularly in the brain, has been associated with human diseases including the neurodegenerative disorders Wilson and Alzheimer’s disease. In this context, astrocytes play an important role in the regulation of the copper homeostasis in the brain and likely in the prevention against neuronal toxicity, consequently pointing them out as a potential target for the neurotoxicity of copper. Major toxic mechanisms are discussed to be directed against mitochondria probably via oxidative stress. However, the toxic potential and mode of action of copper in astrocytes is poorly understood, so far.MethodsIn this study, excess copper levels affecting human astrocytic cell model and their involvement in the neurotoxic mode of action of copper, as well as, effects on the homeostasis of other trace elements (Mn, Fe, Ca and Mg) were investigated.ResultsCopper induced substantial cytotoxic effects in the human astrocytic cell line following 48 h incubation (EC₃₀: 250 μM) and affected mitochondrial function, as observed via reduction of mitochondrial membrane potential and increased ROS production, likely originating from mitochondria. Moreover, cellular GSH metabolism was altered as well. Interestingly, not only cellular copper levels were affected, but also the homeostasis of other elements (Ca, Fe and Mn) were disrupted.ConclusionOne potential toxic mode of action of copper seems to be effects on the mitochondria along with induction of oxidative stress in the human astrocytic cell model. Moreover, excess copper levels seem to interact with the homeostasis of other essential elements such as Ca, Fe and Mn. Disrupted element homeostasis might also contribute to the induction of oxidative stress, likely involved in the onset and progression of neurodegenerative disorders. These insights in the toxic mechanisms will help to develop ideas and approaches for therapeutic strategies against copper-mediated diseases.     

Effects of iron,copper, zinc,calcium, and magnesium on human lymphocytes in culture

The effects of simultaneous changes of calcium, magnesium, iron, copper, and zinc concentrations were evaluated in normal human T and B lymphocytes, cultured in cation-depleted media. Optimal concentrations for thymidine incorporation (TI) in both cell populations were Fe and Zn 15 μM and Cu 5 μM; for t cells Ca 2 mM and Mg 4 mM; for B cells Ca 4 mM and Mg 6 mM. TI decreased with increasing molarity of cations and the decrease was particularly apparent with Cu. Minimal amounts of Ca and Mg (0.5 mM) were necessary for growth, even in presence of optimal concentrations of Fe, Cu, and Zn. Fe and Cu showed synergistic stimulatory effects at low concentrations and synergistic inhibitory effects at high concentrations. Antagonism between Fe and Zn, Cu and Zn, and Ca and Zn was also demonstrated. CD4/CD8 increased with PHA stimulation in presence of Zn, and decreased with ConA stimulation in presence of Zn or Fe. The results demonstrate: (1) the relationship and interdependence of Fe, Cu, and Zn concentrations in modulating the growth of normal lymphocytes; (2) the stimulatory effects of Fe on B cells and Zn on CD8 positive cells; (3) the inhibitory effect of Cu at concentrations lower than those of Fe and Zn; (4) the requirement of Ca and Mg in certain concentration and ratio for the action of the other cations; and (5) the Ca and Mg requirement for the growth of B cells higher than T cells.     

Investigation of Trace Element Content in the Seeds,Pulp, and Peel of Mashui Oranges Using Microwave Digestion and ICP-MS Analysis

Fresh Mashui orange samples were pretreated with microwave digestion using an HNO₃-H₂O₂ system. The levels of Mg, K, Ca, Fe, Mn, Cu, Zn, As, Cd, and Pb in the seeds, pulp, and peel were then determined using inductively coupled plasma mass spectrometry (ICP-MS) combined with collision cell technology (CCT) and kinetic energy discrimination (KED). The standard curve coefficient of determinations of the ten tested elements were between 0.9995 and 0.9999. The instrument detection limit was between 0.112 ng/L and 3.05 ng/mL. The method detection limit was between 0.0281 and 763 ng/g. The average recovery rate was between 85.0 and 117%. The current results showed that Mashui oranges are rich in three elements, namely Mg, K, and Ca. The concentrations of K and Ca were significantly higher than that of Mg in the peel. The content of K was the highest in the seeds. Fe, Mn, Cu, and Zn had the second highest concentrations, and Fe was the highest in the seeds, while Cu was the lowest in the peel. As, Cd, and Pb (hazardous elements) had the lowest concentrations of all the tested elements.     

Inorganic Vanadium Supplementation in Crossbred Calves: Effects on Antioxidant Status,Immune Response and Haemato-Biochemical Attributes

This study aims to investigate the contents of trace elements in the brain and serum of male chickens and the effect of selenium–chromium(VI) interaction. A chronic experimental model was established by supplementing 22.14 mg/kg K₂Cr₂O₇ with 0.00, 0.31, 0.63, 1.25, 2.50, and 5.00 mg/kg Na₂SeO₃ mg/kg B.W. to water for chicken daily. After 14, 28, and 42 days of exposure to the solution, the brain and serum of chickens from each group were collected to detect the levels of Ca, Cu, Mn, Fe, Zn, and Mg by inductively coupled plasma mass spectrometer (ICP-MS). Cr(VI) time-dependently accumulated in the brain and serum. The contents of Cr increased both in the brain and serum with prolonged exposure. Cr contents in the brain and serum decreased in all Se groups compared with those in only Cr-treated groups. Ca contents decreased with prolonged exposure and increasing Se dosage. The contents of Cu and Mn increased on the 28th day but decreased on the 42nd day in the brain and serum. Fe and Zn contents decreased in the serum under prolonged exposure and increased on the 28th day but decreased on the 42nd day in the brain. Cr exposure did not significantly affect Mg contents in the brain but slightly decreased those in the serum. Therefore, appropriate doses of Se affected Cr accumulation, leading to adjustments in the contents and correlations of trace elements.     

Room temperature solvent extraction for simple and fast determination of total concentration of Ca,Cu, Fe,Mg, Mn,and Zn in bee pollen by FAAS along with assessment of the bioaccessible fraction of these elements using in vitro gastrointestinal digestion

Background and aimBee pollen is recognized to be a source of different nutrients, including minerals. As a food supplement, its quality and safety due to concentrations of essential macro- and microelements, and harmful trace elements has to be verified. Fast and simple element analysis of bee-collected pollen can be regarded as an important part of its quality assurance and control. The present study aimed at developping a new method for determination of selected elements (Ca, Cu, Fe, Mg, Mn, Zn) of bee pollen based on solvent extraction and completely avoiding a high temperature treatment with concentrated reagents. In addition, in vitro gastrointestinal digestion was used to assess bioavailability of elements from this food supplement.MethodsBee pollen samples were dried and pulverized. Total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn were determined by flame atomic absorption spectrometry (FAAS) in sample solutions obtained by wet digestion (WD) in concentrated HNO₃ or alternatively by solvent extraction (SE) with diluted solutions of HNO₃. Gastrointestinal digestion was mimicked using simulated solutions of gastric and intestinal juices followed by determination of Ca, Cu, Fe, Mg, Mn and Zn concentrations in the bioaccessible fraction by FAAS.ResultsA new simple and fast method for determination of total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee pollen was developed and validated. The method combined room temperature, two-hour SE with 0.5 mol L⁻¹ HNO₃ with FAAS measurements versus simple standard solutions. It provided precision within 1–5 % and trueness better than 8%, and was shown to be suitable for fast analysis of different polyfloral bee pollens. In vitro gastrointestinal digestion revealed that elements were well (70–85 % for Ca, Mg) and fairly (27–43 % for Cu, Fe, Mn, and Zn) bioaccessible from bee pollen. By pouring with water and swelling overnight, bioaccessibility of studied elements from such prepared bee pollen was increased on average by less than 15 % (Mn), 20 % (Ca, Cu, Fe, Zn) or 30 % (Mn).ConclusionsAvoiding long-lasting, high-temperature wet digestion with concentrated reagents, the proposed sample treatment along with FAAS provided precise and true results of total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee pollen. The method was simple and fast, and enabled to analyze a higher number of samples. Simulated gastrointestinal digestion of bee pollen have shown for the first time that Ca and Mg are the most bioaccessible from this bee product. Bioaccessibility of Cu, Fe, Mg, and Zn from bee pollen are close to or lower than 40 %.     

ICP-AES analysis in sesame on the root rot disease incidence

Five different sesame varieties namely CO-1, VRI-1, VRI-2, TMV-3 and TMV-4 are grown in different trial plots with three treatments viz., control (T₁), chemical fertiliser (T₂) and organic manure (T₃). Diseased and healthy roots are collected fieldwide using standard procedures. Roots are subjected to ICP-AES analysis and the elemental status of the diseased and healthy roots are estimated. A correlation between the elements (Ca, K, Na, Mg, Fe, Cu, Zn) of healthy and diseased plants with reference to manure treatment and different varieties has been attempted. It could be suggested that lowering the concentration of Ca, Na, Mg and Fe and increasing the concentration of K, Cu and Zn in the soil with T₃ treatment may very much reduce root rot disease occurrence.     

Effects of exogenous nitric oxide on photosynthesis,antioxidative ability,and mineral element contents of perennial ryegrass under copper stress

A hydroponics experiment was conducted to test the effects of sodium nitroprusside (SNP, a donor of NO) supplied with different concentrations on copper (Cu) toxicity in ryegrass seedlings (Lolium perenne L.). Excess Cu (200 µM) reduced chlorophyll content, resulting a decrease in photosynthesis. Cu stress induced the production of hydrogen peroxide (H₂O₂) and superoxide anion (O₂^{? ?}), leading to malondialdehyde (MDA) accumulation. Furthermore, activities of antioxidant enzymes in Cu-treated seedlings such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were decreased. In addition, Cu stress inhibited the uptake of K, Mg, Fe, and Zn and increased Ca content in roots. Moreover, in leaves of Cu-stressed seedlings, K, Fe, and Zn contents were decreased and the contents of Ca and Mg were not affected significantly. In Cu-treated seedlings, Cu concentration in roots was higher than in leaves. Addition of 50, 100, 200 µM SNP in Cu-mediated solutions increased chlorophyll content and photosynthesis, improved antioxidant enzyme activities, reduced Cu-induced oxidative damages, kept intracellular ion equilibrium under Cu stress, increased Cu concentration in roots and inhibited Cu accumulation in leaves. In particular, addition of 100 µM SNP had the best effect on promoting growth of ryegrass seedlings under Cu stress. However, the application of 400 µM SNP had no obvious alleviating effect on Cu toxicity in ryegrass seedlings.     

Effect of trace elements on surface hydrophobicity and adherence of Escherichia coli to uroepithelial cells

Trace elements have significant effect on the physiology of bacteria. Variation in the concentration of trace elements may affect the expression of virulence by microorganisms. The effect of trace elements on hydrophobicity and adherence of E.coli to uroepithelial cells was studied. Increasing concentrations of Ca2+, Mg2+, Fe3+ and Zn2+ significantly decreased the surface hydrophobicity. Toxic trace elements like Co2+, Cu2+, Mn2+ and Ni2+ did not alter surface hydrophobicity. With regards to adherence of E.coli to uroepithelial cells, only Mg2+ had significant effect. Toxic trace elements decreased the rate of cell adherence. The pathogenic strains of E.coli showed higher surface hydrophobicity and better cell adherence compared to the nonpathogenic strains. There was good correlation between surface hydrophobicity and cell adherence at higher concentrations (0.1 to 0.2mM) of Fe2+ and Zn2+. The results indicated that trace elements can significantly affect surface hydrophobicity and adherence of E.coli to uroepithelial cells. Such effect may have a significant impact on the initial stages of bacterial infection.     

Chemical bioimaging for the subcellular localization of trace elements by high contrast TEM,TEM/X-EDS,and NanoSIMS

Chemical bioimaging offers an important contribution to the investigation of biochemical functions, biosorption and bioaccumulation processes of trace elements via their localization at the cellular and even at the subcellular level. This paper describes the combined use of high contrast transmission electron microscopy (HC-TEM), energy dispersive X-ray spectroscopy (X-EDS), and nano secondary ion mass spectrometry (NanoSIMS) applied to a model organism, the unicellular green algae Chlamydomonas reinhardtii. HC-TEM providing a lateral resolution of 1 nm was used for imaging the ultrastructure of algae cells which have diameters of 5–10 μm. TEM coupled to X-EDS (TEM/X-EDS) combined textural (morphology and size) analysis with detection of Ca, P, K, Mg, Fe, and Zn in selected subcellular granules using an X-EDS probe size of approx. 1 μm. However, instrumental sensitivity was at the limit for trace element detection. NanoSIMS allowed chemical imaging of macro and trace elements with subcellular resolution (element mapping). Ca, Mg, and P as well as the trace elements Fe, Cu, and Zn present at basal levels were detected in pyrenoids, contractile vacuoles, and granules. Some metals were even localized in small vesicles of about 200 nm size. Sensitive subcellular localization of trace metals was possible by the application of a recently developed RF plasma oxygen primary ion source on NanoSIMS which has shown good improvements in terms of lateral resolution (below 50 nm), sensitivity, and stability. Furthermore correlative single cell imaging was developed combining the advantages of TEM and NanoSIMS. An advanced sample preparation protocol provided adjacent ultramicrotome sections for parallel TEM and NanoSIMS analyses of the same cell. Thus, the C. reinhardtii cellular ultrastructure could be directly related to the spatial distribution of metals in different cell organelles such as vacuoles and chloroplast.     

Neuroprotective Effects of Farnesene Against Hydrogen Peroxide-Induced Neurotoxicity In vitro

Oxidative stress is highly damaging to cellular macromolecules and is also considered a main cause of the loss and impairment of neurons in several neurodegenerative disorders. Recent reports indicate that farnesene (FNS), an acyclic sesquiterpene, has antioxidant properties. However, little is known about the effects of FNS on oxidative stress-induced neurotoxicity. We used hydrogen peroxide (H₂O₂) exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of different FNS isomers (α-FNS and β-FNS) and their mixture (Mix-FNS) in H₂O₂-induced toxicity in newborn rat cerebral cortex cell cultures for the first time. For this aim, both MTT and lactate dehydrogenase assays were carried out to evaluate cell viability. Total antioxidant capacity (TAC) and total oxidative stress (TOS) parameters were used to assess oxidative alterations. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG) levels in vitro, the comet assay was also performed for measuring the resistance of neuronal DNA to H₂O₂-induced challenge. Our results showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage (comet assay) increased in the group treated with H₂O₂ alone. But pretreatment of FNS suppressed the cytotoxicity, genotoxicity and oxidative stress, which were increased by H₂O₂ in clear type of isomers and applied concentration-dependent manners. The order of antioxidant effectiveness for modulating H₂O₂-induced oxidative stress-based neurotoxicity and genotoxicity is as β-FNS > Mix-FNS > α-FNS.     

Responses of <Emphasis Type="Italic">Typha orientalis</Emphasis> Roots to Pb<Superscript>2+</Superscript> Stress

To investigate phytoremediation potential of Typha orientalis Presl in removing Pb²⁺ from polluted water, relevant experiments were conducted to evaluate responses activated by Pb²⁺ (0.25–2 mM) in T. orientalis roots over a period of ten days. Pb contents in subcellular fractions decreased in the following order: cell wall > organelle > soluble fraction. Most of Pb was located in cell wall and membrane system. Contents of K and Ca declined in T. orientalis roots under Pb²⁺ stress, but an opposite effect was noted for some mineral elements (Mg, Cu, Zn, and Fe). H₂O₂ level increased in a concentration-dependent manner, which induced oxidative stress. However, significant reduction in levels of O ₂ ^·? and malondialdehyde (MDA) were observed in all Pb²⁺ treatment groups. Findings indicated toxicity of Pb²⁺ to T. orientalis in terms of inducing oxidative stress and causing imbalance in mineral elements. However, T. orientalis also resisted Pb²⁺-induced damage through isolation mechanism, which involves cell wall and membrane systems.     

微量元素五项联合红细胞四项检测在小儿缺铁性贫血中的诊断价值

目的:探讨微量元素五项联合红细胞四项检测在小儿缺铁性贫血(IDA)中的诊断价值。方法:选取2013年1月至2016年1月于我院进行治疗的小儿缺铁性贫血(IDA)患儿130例作为缺铁性贫血(IDA)组及同期于我院进行常规体检的健康儿童40例作为对照组。检测和比较其钙、镁、铜、铁、锌、血红蛋白(Hb)、平均红细胞体积(MCV)、平均血红蛋白含量(MCH)、平均血红蛋白浓度(MCHC)水平,并比较微量元素五项、红细胞四项检查以及两者联合对IDA患儿的诊断效能。结果:缺铁性贫血(IDA)组患儿微量元素镁、铁、锌含量以及Hb、MCV、MCH及MCHC水平均明显低于对照组儿童,差异具有统计学意义(P0.05);两组儿童微量元素钙、铜含量比较差异不显著(P0.05)。微量元素五项联合红细胞四项的灵敏度、特异度、阳性预测值及阴性预测值均明显高于微量元素五项和红细胞四项(P0.05)。结论:IDA患儿微量元素镁、铁、锌含量以及Hb、MCV、MCH及MCHC水平较低,微量元素五项联合红细胞四项检测可以提高小儿IDA的检出率。     

Higher order chromatin degradation: implications for neurodegeneration

Higher order chromatin degradation (HOCD) is a hallmark of programmed cell death. HOCD is mediated by enzymatic digestion of the DNA backbone at matrix attachment regions, and ultimately results in the excision of chromatin loops and their oligomers from chromosomes. We have recently demonstrated that hydrogen peroxide (H₂O₂), the major mediator of oxidative stress, rapidly induces HOCD. This demonstration allowed us to characterize several kinetic features of HOCD. Moreover, H₂O₂-induced HOCD provides a mechanistic link between oxidative stress and the pathology of neurodegeneration. Thus, in acute neurodegenerative conditions, which feature severe oxidative stress, H₂O₂-induced HOCD efficiently dismantles the genome, and thus, irreversibly commits cells to death. In chronic neurodegenerative conditions, which feature sublethal but perennial oxidative stress, cells undergo only a partial fragmentation of the genome via H₂O₂-induced HOCD. If unrepaired of improperly repaired, such a partial fragmentation leads to the generation and accumulation of somatic mutations that are likely to play the key role in delayed degeneration and death of neural cells.     

Effects of nitric oxide and Fe supply on recovery of Fe deficiency induced chlorosis in peanut plants

The effects of nitric oxide (NO) and/or iron (Fe) supplied to Fe deficient plants have been investigated in peanut (Arachis hypogaea L.) grown in Hoagland nutrient solution with or without Fe. Two weeks after Fe deprivation, recovery was induced by addition of 250 μM sodium nitroprusside (SNP, a NO donor) and/or 50 μM Fe (Fe-EDTA) to the Fe deprived (-Fe) nutrient solution. Activities of antioxidant enzymes, leaf chlorophyll (Chl), and active Fe content decreased, whereas activities of H⁺-ATPase, ferric-chelate reductase (FCR), nitrate reductase, and nitric oxide synthase and NO production increased in Fe deficient plants, consequently an Fe chlorosis symptom appeared obviously. In contrast, these symptoms disappeared gradually after two weeks with NO and/or Fe supply, which caused an increases in leaf Chl and active Fe content, especially following by co-treatment with NO and Fe to values found in Fe sufficient plants. Increased activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and decreased accumulation of reactive oxygen species (H₂O₂, O ₂ ^?? ) and malondialdehyde enhanced the ability of resistance to oxidative stress. Supplied NO alone had the obvious effect on increased NO production and on activity of H⁺-ATPase and FCR, whereas root length and root/shoot ratio were most effectively increased by Fe supplied alone. Co-treatment with NO and Fe did the best effects on recovery peanut chlorosis symptoms by significantly increased Chl and available Fe content and adjusted distribution of Fe and other mineral elements (Ca, Mg, and Zn) in both leaves and roots.     

Neuroprotective Effects of Theaflavins Against Oxidative Stress-Induced Apoptosis in PC12 Cells

Oxidative stress can induce neuronal apoptosis via the production of superoxide and hydroxyl radicals. This process is as a major pathogenic mechanism in neurodegenerative disorders. In this study, we aimed to clarify whether theaflavins protect PC12 cells from oxidative stress damage induced by H₂O₂. A cell model of PC12 cells undergoing oxidative stress was created by exposing cells to 200 μM H₂O₂ in the presence or absence of varying concentrations of theaflavins (5, 10, and 20 μM). Cell viability was monitored using the MTT assay and Hoechst 33258 staining, showing that 10 μM theaflavins enhanced cell survival following 200 μM H₂O₂ induced toxicity and increased cell viability by approximately 40?%. Additionally, we measured levels of intracellular reactive oxygen species (ROS) and antioxidant enzyme activity. This suggested that the neuroprotective effect of theaflavins against oxidative stress in PC12 cells is derived from suppression of oxidant enzyme activity. Furthermore, Western blot analyses indicated that theaflavins downregulated the ratio of pro-apoptosis/anti-apoptosis proteins Bax/Bcl-2. Theaflavins also downregulated the expression of caspase-3 compared with a H₂O₂-treated group that had not been treated with theaflavins. Interestingly, this is the first study to report that the four main components of theaflavins found in black tea can protect neural cells (PC12) from apoptosis induced by H₂O₂. These findings provide the foundations for a new field of using theaflavins or its source, black tea, in the treatment of neurodegenerative diseases caused by oxidative stress.     

Elemental composition of subcellular structures of human spermatozoa. A study by energy dispersive analysis of X-ray

The elemental chemical composition of selected intracellular structures (membrane, mitochondria and nucleus) of the human spermatozoa were studied by the combined use of energy dispersive analyses of X-rays and electron microscopy and the results compared with those obtained by atomic absorption spectrometry of isolated subcellular structures (heads and tails) of the same type of cells. In nuclei EDAX studies showed the following relative concentrations P>S>Mg, K, Zn, Si>Ca, Fe. The mitochondrial spectrum showed the presence of important concentrations of Ca>Fe, K, P>Mg, S>Mn. Human spermatozoa membrane was found to be particularly rich in Ca, S and $\text{Z}$n. By atomic absorption it was found that K was the most concentrated element in both isolated fractions (heads and tails). Sperm heads were found richer than tails in Na, Cu and Zn, while sperm tails had higher concentrations of Ca. The zinc concentration of human sperm cells and their subfractions was considerably higher than the reported Zn concentration in any other human cells or their subfractions.     

The Rengen Grassland Experiment: relationship between soil and biomass chemical properties, amount of elements applied, and their uptake

The Rengen Grassland Experiment (RGE) was established in the Eifel Mountains (Germany) on a low productive Nardetum in 1941. Since then, the following fertilizer treatments have been applied with a late two-cut system: unfertilized control, Ca, CaN, CaNP, CaNPKCl and CaNPK₂SO₄. We aimed to understand how concentrations of macro (N, P, K, Ca and Mg), micro (Cu, Fe, Mn and Zn) and trace (As, Cd, Cr, Ni and Pb) elements in the plant biomass were affected by long-term fertilizer application, soil chemical properties and biomass production. In 2008, biomass samples from the first cut (early July) and the second cut (mid-October) were collected and analyzed. The simultaneous application of N, P and K decreased nitrogen concentration in the aboveground biomass, but substantially increased biomass production. Late cutting management decreased forage quality in highly productive more than in low productive plant communities. The concentrations of P and K in the plant biomass were positively related to P and K application and, therefore, to plant available P and K concentrations in the soil. The concentrations of some micro (Fe, Mn and Zn) and trace (As, Cd, Cr, Ni and Pb) elements in the plant biomass were negatively correlated with the amount of elements supplied by fertilizers and biomass production, probably because of the dilution effect. Long-term fertilizer application resulted in the accumulation of macro (P, Ca and Mg), micro (Fe and Mn) and trace (As and Cr) elements in the soil, but in many cases this accumulation was not connected with an increase in the concentrations of these elements in the plant biomass. Nutritional status, as indicated by the biomass N:P ratio, was consistent with N or P limitation as indicated by the nitrogen and phosphorus nutrition indices. Furthermore, additional K (co-)limitation was indicated by the N:K and K:P ratios in the biomass from the NP treatment. The results from the RGE indicate that there is no simple positive relationship between the applied elements and their concentrations in the plant biomass.     

Flavonoid Baicalein Modulates H<Subscript>2</Subscript>O<Subscript>2</Subscript>-Induced Mitogen-Activated Protein Kinases Activation and Cell Death in SK-N-MC Cells

It is believed that ROS-induced oxidative stress triggers numerous signaling pathways which are involved in neurodegenerative diseases, including Alzheimer’s disease. To find the effective drugs for neurodegenerative diseases, the deep delve into molecular mechanisms underlie these diseases is necessary. In the current study, we investigated the effects of flavonoid baicalein on H₂O₂-induced oxidative stress and cell death in SK-N-MC cells. Our results revealed that the treatment of SK-N-MC cells with H₂O₂ led to a decrease in cell viability through phosphorylation and activation of extracellular signal-regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs) pathways followed by increase in Bax/Bcl2 ratio and initiation of caspase-dependent apoptotic pathways. In addition, our results showed that the exposure of SK-N-MC cells to H₂O₂ ended up in reduction of glutathione (GSH) levels of SK-N-MC cells via JNK/ERK-mediated down-regulation of γ-glutamyl-cysteine synthetase (γ-GCS) expression. Our results demonstrated that flavonoid baicalein protected against H₂O₂-induced cell death by inhibition of JNK/ERK pathways activation and other key molecules in apoptotic pathways, including blockage of Bax and caspase-9 activation, induction of Bcl-2 expression and prevention of cell death. Baicalein supported intracellular defense mechanisms through maintaining GSH levels in SK-N-MC cells by the removal of inhibition effects of JNK/ERK pathways from γ-GCS expression. In addition, baicalein attenuated lipid and protein peroxidation and intracellular reactive oxygen species in SK-N-MC cells. In accordance with these observations, baicalein can be a promising candidate in antioxidant therapy and designing of natural-based drug for ROS-induced neurodegenerative disorders.