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Current research focused on the potential role of zinc oxide nanoparticles (ZnONPs) and potassium (K+) in mitigation of arsenic (As) toxicity in Vicia faba L. seedlings. Faba bean seedlings were grown for 30 days in potted soil. As stress curtailed root and shoot length, chlorophyll (Chl) content and net photosynthetic rate in V. faba seedlings. However, ZnONPs and K+ curtailed As stress in faba bean seedling through enhanced activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) enzyme. Furthermore, ZnONPs and K+ significantly enhanced cysteine (Cys) content and serine acetyletransferase (SAT) activity in faba bean seedling exposed to As-toxificated soil. Application of ZnONPs and K+ curtailed superoxide ionic content and hydrogen peroxide (H2O2) accumulation in V. faba seedlings exposed to As-polluted soil. Nitric oxide (NO) content also increased in faba bean seedlings treated with ZnONPs and K+ in normal and As-polluted soil. As stress alleviation was credited to reduce As uptake in faba bean seedlings treated with synergistic application of ZnONPs and K+. It is proposed that K+ interaction with nanoparticles can be exploited at molecular level to understand the mechanisms involved in abiotic stress tolerance.

Osmotic or pneumatically-generated pressure gradients can be used in membrane-based filtration processes to preconcentrate biofluid samples for enhanced signal and increased sensitivity in diagnostic sensing applications.

هدف البحث الحالي إلى تنمية التعلم المنظم ذاتيا والتحصيل الأكاديمي لدى طالبات التعليم الأساسي في مادة العلوم وذلك باستخدام استراتيجيات التدريس الاستقرائي، وتكونت عينة البحث من (20) طالبة من طلبة التعليم الأساسي، قد تراوحت أعمارهن ما بين (14- 15) عاما، بمتوسط عمري قدره (14.57) وانحراف معياري قدره (0.40), وتم تقسيم العينة إلى مجموعتين التجريبية درست باستخدام استراتيجية التدريس الاستقرائي والمجموعة الضابطة درست باستخدام الطريقة الاعتيادية (التقليدية)، قسمت بالتساوي على المجموعتين، وتكونت أدوات الدراسة من مقياس التعلم المنظم ذاتيا والتحصيل الاكاديمي، (من إعداد الباحثة)، وأسفرت النتائج عن فعالية استراتيجية التدريس الاستقرائي في تنمية التعلم المنظم ذاتيا والتحصيل الأكاديمي لدى طلبة التعليم الأساسي في مادة العلوم لصالح المجموعة التجريبية.

A Kunitz-type trypsin inhibitor protein has been purified and characterized from seeds of Acacia nilotica L. LC-MS/MS analysis of Acacia nilotica trypsin inhibitor (AnTI) provided the N-terminal fragment of 11 amino acids which yielded 100% identity with already reported Kunitz-type trypsin inhibitor protein of Acacia confusa (AcTI) in UniProtKB database search. SDS-PAGE showed a single band of ~21 kDa under nonreduced condition and appearance of a daughter band (17 kDa) in the presence of β-mercaptoethanol indicating the presence of interchain disulfide linkage typical for Kunitz-type trypsin inhibitors. AnTI was purified from seed extract by using a combination of anion exchange and gel filtration chromatography. Since AnTI showed maximum homology with AcTI, a molecular structure of AcTI was predicted which showed highly β-sheeted molecular conformation similar to crystallographic structure of Enterolobium contortisiliquum trypsin inhibitor (EcTI). AnTI (20 µg) produces significant population inhibition against different human pathogenic bacteria along strong antifungal activity (50 µg). Entomotoxin potential of AnTI was evaluated against two stored grain insect pests Tribolium castaneum (Herbst) (Tenebrionidae: Coleoptera) and Sitophilus oryzae (Linnaeus) (Curculionidae: Coleoptera). Statistically significant mortality of T. castaneum adults was observed at 1.5 mg after 15 days in comparison to control. Additionally, number of total eggs, larvae, pupae, adults, and their male/female ratio were also severely reduced in comparison to control. Similarly, two generation progeny of S. oryzae was studied after mixing AnTI with rice kernels. Mean percent mortality of adult population was significantly higher after 9 days of exposure in comparison to control group. AnTI significantly reduced the F1 generation while little mortality was observed for F2 generation. Exploration of such potent molecules is the prerequisite of our time regarding the anticipation of postantibiotic era and the development of insect resistance against chemical pesticides.

Beans and lentils are good sources of total phenolic contents and possessed excellent free radical scavenging activity. This study was aimed to assess the total phenolic compounds (TPCs) and antioxidant activity of dried and germinated beans and lentils. The total phenolics contents were extracted from seven types of beans and lentils by using 50% (v/v) aqueous ethanol. The TPCs and antioxidant activities were analyzed using Folin-Ciocalteu and DPPH (2, 2-diphenyle-1-picrylhydrazyl radical), ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonate) assays, respectively. The legumes showed the highest total phenolic contents (TPCs) and antioxidant capacity by DPPH and ABTS scavenging activity (p < 0.05) in germinated samples. The germinated beans and lentils contained more total phenolic contents that decrease significantly in dried beans. This study also suggested that germinated beans are a valuable source of commercial natural antioxidants.

While there are many chip models that simulate the air-tissue interface of the respiratory system, only a few represent the upper respiratory system. These chips are restricted to unidirectional flow patterns that are not comparable to the highly dynamic and variable flow patterns found in the native nasal cavity. Here we describe the development of a tunable nose-on-chip device that mimics the air-mucosa interface and is coupled to an air delivery system that simulates natural breathing patterns through the generation of bi-directional air flow. Additionally, we employ computational modeling to demonstrate how the device design can be tuned to replicate desired mechanical characteristics within specific regions of the human nasal cavity. We also demonstrate how to culture human nasal epithelial cell line RPMI 2650 within the lab-on-chip (LOC) device. Lastly, Alcian Blue histological staining was performed to label mucin proteins, which play important roles in mucous secretion. Our results revealed that dynamic flow conditions can increase mucous secretion for RPMI 2650 cells, when compared to no flow, or stationary, conditions.

Background: Fungi and insect pests ruin stored crop grain, which results in millions of dollars of damage, presenting an ongoing challenge for farmers in addition to diminishing the safety of stored food. A wide-range defensive system against pathogens is needed to reduce or even eliminate the dependence of the crop yield upon the use of pesticides. Plant defensins (γ-thionins) are antimicrobial peptides (AMPs) that are a component of the host defense system. They are known to interact with cell membranes to exhibit antifungal and insecticidal activity. They exhibit a broad range of activities against fungi and insects and are effective at low concentrations. Thionins act on membranes, greatly reducing the development of pathogen resistance. Objective: The aim of this study is to investigate a bioactive molecule that acts against fungal pathogens and stored grain insect pests. Method: γ-thionin protein was extracted from Brassica oleracea L. var. capitata f. alba (white cabbage) seed powder in phosphate buffer (100 mM, pH 7.0) and was identified by MALDI-TOF/TOF. The crude extract was subjected to 70% ammonium sulfate saturation followed by gel filtration chromatography. The disc diffusion assay along with a microtiter bioassay was used to determine the antifungal activity of the protein against phytopathogenic fungi. The insecticidal efficacy was evaluated by feeding insect pests with food contaminated with the purified protein. Additionally, an in silico molecular structure prediction study of the protein was performed using Auto Dock Vina for molecular docking of the protein with either fungal membrane moieties or α-amylase from Tenebrio molitor L. MD simulations of protein-ligand complexes were conducted using Schrodinger’s Desmond module. Results: γ-Thionin (BoT) was purified from white cabbage seeds and showed 100% homology with thionin (Brassica oleracea L. var. viridis) and 80% homology with defensin-like protein 1 (Raphanus sativus L.), respectively. BoT significantly inhibited the mycelial growth of Aspergillus niger van Tieghem and Aspergillus flavus Link at a concentration of 2 μM. Similarly, 0.12 μM BoT treatment resulted in significant mortality of Tribolium castaneum Herbst and Sitophilus oryzae L. Molecular docking and MD simulation of BoT confirmed the strong binding affinity with fungal membrane moieties (phosphatidylinositol 4,5-bisphosphate and phosphatidic acid), which causes disruption of the cell membrane and leakage of the cellular contents, leading to cell death. BoT blocked the active site of α-amylase, and as a result of the inactivation of this gut enzyme, the digestive systems of insects were disturbed, resulting in their deaths. Conclusion: This study revealed that γ-thionin is a good antifungal and insecticidal agent that could be used as an alternate to fungicides and insecticides.

Current research focused on the potential role of zinc oxide nanoparticles (ZnONPs) and potassium (K+) in mitigation of arsenic (As) toxicity in Vicia faba L. seedlings. Faba bean seedlings were grown for 30days in potted soil. As stress curtailed root and shoot length, chlorophyll (Chl) content and net photosynthetic rate in V. faba seedlings. However, ZnONPs and K+ curtailed As stress in faba bean seedling through enhanced activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) enzyme. Furthermore, ZnONPs and K+ significantly enhanced cysteine (Cys) content and serine acetyletransferase (SAT) activity in faba bean seedling exposed to As-toxificated soil. Application of ZnONPs and K+ curtailed superoxide ionic content and hydrogen peroxide (H2O2) accumulation in V. faba seedlings exposed to As-polluted soil. Nitric oxide (NO) content also increased in faba bean seedlings treated with ZnONPs and K+ in normal and As-polluted soil. As stress alleviation was credited to reduce As uptake in faba bean seedlings treated with synergistic application of ZnONPs and K+. It is proposed that K+ interaction with nanoparticles can be exploited at molecular level to understand the mechanisms involved in abiotic stress tolerance.

Made available in DSpace on 2021-06-25T10:22:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-01 The skin serves a substantial number of physiological purposes and is exposed to numerous biological and chemical agents owing to its large surface area and accessibility. Yet, current skin models are limited in emulating the multifaceted functions of skin tissues due to a lack of effort on the optimization of biomaterials and techniques at different skin layers for building skin frameworks. Here, we use biomaterial-based approaches and bioengineered techniques to develop a 3D skin model with layers of endothelial cell networks, dermal fibroblasts, and multilayered keratinocytes. Analysis of mechanical properties of gelatin methacryloyl (GelMA)-based bioinks mixed with different portions of alginate revealed bioprinted endothelium could be better modeled to optimize endothelial cell viability with a mixture of 7.5% GelMA and 2% alginate. Matrix stiffness plays a crucial role in modulating produced levels of Pro-Collagen I alpha-1 and matrix metalloproteinase-1 in human dermal fibroblasts and affecting their viability, proliferation, and spreading. Moreover, seeding human keratinocytes with gelatin-coating multiple times proved to be helpful in reducing culture time to create multiple layers of keratinocytes while maintaining their viability. The ability to fabricate selected biomaterials for each layer of skin tissues has implications in the biofabrication of skin systems for regenerative medicine and disease modeling. Center for Minimally Invasive Therapeutics (C-MIT) University of California-Los Angeles Bioprocess and Biotechnology Department Sãao Paulo State University (Unesp) School of Pharmaceutical Sciences, Km 01 Araraquara-Jau Road São Paulo State University (Unesp) Institute of Chemistry, 55 Prof. Francisco Degni Street Terasaki Institute for Biomedical Innovation Department of Bioengineering Henry Samueli School of Engineering and Applied Sciences University of California-Los Angeles Department of Electrical and Electronic Engineering The University of Hong Kong College of Pharmacy Kangwon National University U.S. Air Force Research Laboratory 711th Human Performance Wing Airman Systems Directorate Bioeffects Division Molecular Bioeffects Branch (USAFRL/711HPW/RHDJ) Department of Radiological Sciences University of California-Los Angeles Department of Biomedical Engineering Michigan State University Department of Chemical and Biomolecular Engineering Henry Samueli School of Engineering and Applied Sciences University of California-Los Angeles Jonsson Comprehensive Cancer Centre University of California Bioprocess and Biotechnology Department Sãao Paulo State University (Unesp) School of Pharmaceutical Sciences, Km 01 Araraquara-Jau Road São Paulo State University (Unesp) Institute of Chemistry, 55 Prof. Francisco Degni Street

The present study was designed to investigate the role of manganese (Mn) as an antioxidant element. In vitro experiments have been conducted to evaluate the ability of Mn in scavenging oxygen free radicals. Superoxide (O ·− ) and hydroxyl (OH ·− ) radicals were generated in vitro by using xanthine and xanthine oxidase system and fenton reactions respectively. Different concentrations of Mn (II) and Mn (III) were used in the reaction mixture to evaluate free radical scavenging ability of Mn. The results indicated that Mn scavenged superoxide radicals at nanomolar concentrations whereas hydroxyl radicals were scavenged at micromolar concentrations. In addition, Mn-superoxide dismutase (SOD) activity was measured in different regions of brain in adult male rats treated with MnCl 2 . The results showed that Mn-SOD activity increased in Mn treated animals. Therefore, the data support the hypothesis that Mn is one of the essential elements which can protect against oxidative damage, however, at higher concentrations Mn can be neurotoxic by generating the free radicals.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been shown to be toxic by inducing oxygen free radicals in the mammalian nervous system, especially in the nigrostriatal dopaminergic system. The present study was designed to compare the toxic effects of MPP+, the active metabolite of MPTP, in MN9D neuronal cells that exhibit relatively low levels of catalase activity, as compared to CHO cells, which exhibit high levels of catalase activity. The survival of the MN9D cells in the presence of 250 microM MPP+ was less than 10%, whereas CHO cells exhibited 70% survival at the same concentration of MPP+. The ED50 values of MPP+ in MN9D and CHO cell lines were 60-600 microM, respectively. MN9D cells contain less catalase, an enzyme believed to be involved in the detoxification of free radicals compared to CHO cells. The catalase activity was 2 Units/mg protein in MN9D cells and 30 U/mg protein in CHO cells. The catalase activity in CHO cells increased with increasing MPP+ concentrations from 100-500 microM, however, it decreased at 1 mM MPP+. In contrast, catalase activity in MN9D remained the same at all MPP+ concentrations. When the CHO cells were pre-treated with 10-25 mM 3-aminotriazole (3-AT), which inhibits catalase activity, and exposed to MPP+ at various concentrations, they became susceptible to MPP+. It is evident from these data that the differential susceptibility to MPP+ in these two cell lines are due to differences in catalase activity. In addition, the inhibition of constituentive catalase activity in CHO cells by 3-AT treatment enhances their susceptibility. In conclusion, the study demonstrates that catalase activity represents an important defence mechanism in MPTP-induced toxicity.

The present study was designed to investigate if chronic exposure to manganese (Mn) produces an effect on antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx) activities and reduced glutathione (GSH) content in different regions of rat brain. Adult male Sprague-Dawley (CD) rats were dosed with 0, 2.5 or 5.0 mg MnCl2/kg, for 3 months (5 days/week). The activity of total superoxide dismutase did not vary significantly in any region of the brain with either 2.5 or 5.0 mg MnCl2/kg. A significant increase of Mn-superoxide dismutase (Mn-SOD) activity was attained in hippocampus, cerebellum and brain stem. The Cu, Zn-superoxide dismutase activity was reduced in all regions of the brain, however, reduction was not statistically significant. No significant effect of Mn on glutathione peroxidase activity was observed in any region of the brain. Glutathione content was significantly reduced in cerebellum, whereas, no change was observed in other brain regions. The results show that chronic exposure to manganese significantly increased the Mn-superoxide dismutase activity in selected brain regions. Therefore, increased Mn-SOD may enhance the antioxidant ability of the brain to reduce oxidative stress. © 1997 John Wiley & Sons, Ltd.

Nanoparticles (NPs) are being implemented in a wide range of applications, and it is critical to proactively investigate their toxicity. Due to the extensive range of NPs being produced, in vitro studies are a valuable approach for toxicity screening. Key information required to support in vitro toxicity assessments include NP stability in biologically relevant media and fate once exposed to cells. Hyperspectral microscopy is a sensitive, real-time technique that combines the use of microscopy and spectroscopy for the measurement of the reflectance spectrum at individual pixels in a micrograph. This method has been used extensively for molecular imaging with plasmonic NPs as contrast agents (Aaron et al., Opt Express 16:2153-2167, 2008; Kumar et al., Nano Lett 7:1338-1343, 2007; Wax and Sokolov, Laser Photon Rev 3:146-158, 2009; Curry et al., Opt Express 14:6535-6542, 2006; Curry et al., J Biomed Opt 13:014022, 2008; Cognet et al., Proc Natl Acad Sci U S A 100:11350-11355, 2003; Sokolov et al., Cancer Res 63:1999-2004, 2003; Sönnichsen et al., Nat Biotechnol 23:741-745, 2005; Nusz et al., Anal Chem 80:984-989, 2008) and/or sensors (Nusz et al., Anal Chem 80:984-989, 2008; Ungureanu et al., Sens Actuators B 150:529-536, 2010; McFarland and Van Duyne, Nano Lett 3:1057-1062, 2003; Galush et al., Nano Lett 9:2077-2082, 2009; El-Sayed et al., Nano Lett 5:829-834, 2005). Here we describe an approach for using hyperspectral microscopy to characterize the agglomeration and stability of plasmonic NPs in biological media and their interactions with cells.

Lead accumulation as determined by Atomic Absorbtion Spectroscopy was found to be higher in the roots than in the aerial parts of the aquatic plant Eichhornia crassipes Mart (Solms). However, Pb accumulation in the leaves of the Eichhornia plants had more significant effects with respect to eco‐toxicological studies. The hyacinth weevils Neochetina eichhornae feeding on lead treated plants bioaccumulated about 5–10% of Pb through the trophic levels of food chain. Studies on the biochemical changes in these insects revealed a drastic decline in the protein content with an increase in the free amino acid pool. The higher activity of alanine and aspartate amino‐transferases implied their role in metal stress conditions. This study demonstrated the biotransfer of a toxic metal Pb from the aquatic environment to the insects via the trophic levels of food chain ‐ a unique model system for ecotoxicological studies.

Hydrogen peroxide-resistant Chinese hamster ovary (CHO) cells displayed cross-resistance to CdCl2, HgCl2 and NaAsO2 but not to Na2Cr2O7, ZnCl2, NiCl2 and CuSO4. Resistance to hydrogen peroxide and to the metals was partially retained by these cells for many generations despite growth in drug-free medium. The loss of resistance was a slow process, and was different for the various metal compounds. Cell variants had a slightly higher content of non-protein intracellular thiols (NPSH) than sensitive cells. This biochemical feature did not seem to be the cause of resistance to CdCl2 but accounted for at least part of the resistance to HgCl2 and NaAsO2. Increased metallothionein synthesis did not seem to be responsible for the metal-resistant phenotype. These results suggest that resistance to specific metal compounds in cultured mammalian cells adapted to hydrogen peroxide is dependent on a number of factors which differ for the various metal compounds and which are characterized by a different stability.

The total protein distribution as a function of metal bioaccumulation in the weevils Neochetina eichhornae Warner through the trophic levels of the food chain was investigated. The accumulation of metals in insects was almost linear for all the metal concentrations tested. Mercury, Cd, Pb, and Zn induced dramatic differences in protein profiles in the insects in the SDS-Gel electrophoretic patterns. Of 40–50 μg/100 mg of metal concentrations of Cd, Pb, and Zn estimated in the leaves of Eichhornae only about 4–9% could be estimated from the insect cell extract. Mercury concentration in the leaves was still lower i.e., 10–19% μg/100 mg of metal conc. and the biotransfer of Hg into insect bodies was about 2–4%. It is concluded that the two metals Pb and Zn resulted in the selective synthesis and accumulation of proteins in the 70–80 KD range. The possibility of the disappearance of pre-existing proteins in the insects is discussed in the light of metal bioaccumulation.

A concentration of H2O2 resulting in mode one killing of Escherichia coli is more toxic when exposure to the oxidant is performed in complete medium (K medium), as compared to a saline (M9 salts). Inorganic salts (MgSO4 and CaCl2), thiamine or glucose, when added separately, or combined, to M9 salts had no effect on the cytotoxic response to H2O2. In contrast, the lethality of the oxidant was highly dependent on the presence of the amino acids in the incubation medium. The addition of glucose further enhanced this response. Among the seventeen amino acids which are present in the complete amino acid mixture, only two, i.e. L-histidine and L-cystine, were found to increase the toxicity of H2O2. Again, glucose augmented this response. The effect of these amino acids on the growth inhibitory action of hydrogen peroxide was also tested in Chinese Hamster Ovary cells. It was found that L-histidine was capable of increasing the toxicity of the oxidant whereas all the other amino acids did not affect the toxicity of the oxidant. Glucose only slightly augmented this effect of L-histidine. DNA single strand breakage produced by H2O2 was increased by L-histidine and was not significantly modified by the other amino acids. DNA double strand breakage was also shown to occur in cells exposed to H2O2-L-histidine, and this effect was independent on the presence of glucose. These results demonstrate that the cytotoxic response of bacterial and mammalian cells to challenge with H2O2 is highly dependent on the composition of the extracellular milieu.(ABSTRACT TRUNCATED AT 250 WORDS)

Nanoparticles are small sized (1-100 nm) particles derived from transition metals, silver, copper, aluminum, silicon, carbon and metal oxides that can easily cross the blood-brain barrier (BBB) and/or produce damage to the barrier integrity by altering endothelial cell membrane permeability. However, the influence of nanoparticles on BBB integrity is still not well-known. In this investigation, effect of nanoparticles derived from Ag, Al and Cu (50-60 nm) on BBB permeability in relation to brain edema formation was examined in a rat model. Intravenous (30 mg/kg), intraperitoneal (50 mg/kg) or intracerebral (20 microg in 10 microL) administration of Ag, Cu or Al nanoparticles disrupted the BBB function to Evans blue albumin (EBA) and radioiodine in rats 24 h after administration and induced brain edema formation. The leakage of Evans blue dye was observed largely in the ventral surface of brain and in the proximal frontal cortex. The dorsal surfaces of cerebellum showed mild to moderate EBA staining. These effects were most pronounced in animals that received Ag or Cu nanoparticles compared to Al nanoparticles through intravenous routes. These observations are the first to suggest that nanoparticles can induce brain edema formation by influencing BBB breakdown in vivo.

Previous reports from our laboratory show that animals treated with engineered nanoparticles derived from metals for 1 week and subjected to hyperthermia showed enhanced neurotoxicity in terms of blood-brain barrier (BBB) disruption, brain edema formation and cell injury. It appears that nanoparticle induced enhanced oxidative stress leads to increased lipid peroxidation and over-production of hydroxyl radicals are responsible for exacerbation of neurotoxicity in hyperthermia. Therefore, in this investigation, rats (after 1 week administration of Ag or Cu nanoparticles) were treated with a new antioxidant compound H-290/51 (an inhibitor of lipid peroxidation, 50 mg/kg, p.o.) before subjecting them to hyperthermia. One group of nanoparticle treated rat received H-290/51 and were kept at room temperature for comparison. Our results show that H-290/51 significantly attenuated heat stress induced BBB impairment, brain edema formation and neurotoxicity in nanoparticle treated rats. However, no significant diminution of nanoparticle induced BBB breakdown, or neurotoxicity was observed in H-290/51 treated rats kept at room temperature. These observations suggest that nanoparticles aggravate oxidative stress following hyperthermia leading to exacerbation of neurotoxicity through oxidative stress-related mechanisms, not reported earlier.

Present study describes the effect of zinc (Zn) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced dopamine depletion in mice brain. MPTP is a known neurotoxicant primarily causing marked depletion of dopamine (DA) levels in nigrostriatal dopaminergic system. Adult Male C57-mice were intraperitonially injected with 25 mg/kg MPTP in the presence or absence of zinc acetate. Twenty-four hours after treatment animals were sacrificed and DA levels were determined by high performance liquid chromatography in caudate nucleus of control and treated mice. The results showed that there was a marked depletion of DA in MPTP treated mice, whereas no change was observed in DA levels in mice treated with Zn when compare to controls. Interestingly, mice receiving MPTP in conjunction with Zn showed significantly lower DA levels in brain when compare to animals receiving MPTP alone. In summary the data suggest that Zn treatment potentiates depletion of dopamine in MPTP treated mice.

The response of endogenous antioxidants to acute exposure of the mitochondrial inhibitor, 3-nitropropionic acid (3-NPA), was investigated in selected rat brain regions. Rats treated with 3-NPA (30 mg/kg, s.c.) were sacrificed at 30, 60, 90 and 120 min after injection to examine the alterations in reduced glutathione levels (GSH), and activities of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) in the hippocampus (HIP), frontal cortex (FC), and caudate nucleus (CN). CAT activity increased in the HIP 90 min after 3-NPA treatment. While cytosolic copper/zinc SOD (CuZn-SOD) and mitochondrial manganese SOD (Mn-SOD) levels increased in the FC at 120 min, only the Mn-SOD increased in the CN 90 min after treatment. The activity of GPx decreased in the HIP 120 min after 3-NPA injection. When compared with the control, administration of 3-NPA led to GSH depletion in HIP within 120 min. The depletion of GSH and induction of antioxidant enzyme activities after the 3-NPA exposure suggest conditions favorable for oxidative stress.

Based on the inhibition of nitrite formation by generating superoxide from xanthine/xanthine oxidase (X/XO) reaction system, metallothionein (MT) and other sulfhydryl containing amino acids have been selected to test their abilities to scavenge superoxide radicals. Different concentrations of metallothionein and other sulfhydryl containing molecules e.g. cysteine, N-acetyl-cysteine and glutathione, were used to assess superoxide scavenging properties. Metallothionein scavenges superoxide radical in a dose-dependent manner with increasing concentrations as evidenced by the inhibition of nitrite formation. Similar abilities to scavenge superoxide radicals were shown by cysteine, N-acetyl-cysteine. Glutathione also scavenges superoxide radical in a dose-dependent manner. In vitro experiments demonstrated that metallothionein is superior in scavenging superoxide radicals compared to other sulfhydryl molecules such as cysteine, N-acetyl-cysteine and even glutathione. The data, further, suggest that metallothionein-II has a 6-fold higher capacity to scavenge superoxide radical than metallothionein-I. In addition, metallothionein-like protein was isolated from different regions of mouse brain treated with zinc. Brain metallothionein-like protein inhibits nitrite formation as demonstrated by other scavengers; however, the extent of inhibition is different by this protein isolated from different brain regions. The present study suggests that metallothioneins and metallothionein-like proteins isolated from mouse brain act as neuroprotective agents by scavenging superoxide radicals.

It has been proposed that neurodegenerative processes of aging are associated with the generation of reactive oxygen species (ROS) during cellular metabolism. These reactive oxygen species are scavenged by antioxidant enzymes in biological systems. The present study was designed to determine the selective distribution of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase activity and reduced glutathione (GSH) levels in different regions of the C57BL/6N mouse brain and to determine if any alterations occurred with age. Catalase activity did not show any significant change except in cerebellum. Activity of superoxide dismutase was increased with age in all regions of the brain except in hippocampus of 2-yr-old mice. The glutathione peroxidase activity in the caudate nucleus increased in all regions of the brain, however, the activity did not change at one, six and 12 months. A significant increasing pattern of glutathione content was found in the cerebellum and brain stem with age. These data demonstrate that although the level of antioxidant enzymes varied in different regions of the brain, overall the enzyme activities tend to increase with age.

Metal-binding proteins are important components of retroviruses such as human immunodeficiency virus (HIV). Therefore, metals could be used as antiviral agents. However, most metals are toxic for humans with the exception of silver which is toxic only to prokaryotic cells and viruses. In addition, HIV infection causes a decrease in body cysteine. We formed a complex of silver and cysteine, named silver-cysteine. Healthy human lymphocytes were incubated with silver-nitrate or silver-cysteine. Negligible cell survival was seen at 50 μM silver-nitrate. However, in presence of 1 mM cysteine, the viability remained unaffected up to 1 mM of silver. Further, silver inhibition of isolated Na,K-ATPase was easily reversed by cysteine. Thus, non-toxic silver-cysteine could be used as an anti-viral and cysteine-replenishing agent.

Water hyacinth growth is kept under control by the week eating weevils, Neochetina eichhornae (Warner) and N. bruchi (Hustache). Water hyacinth is generally considered an aquatic weed because it clogs waterways, although it has recently been evaluated as a potential biological filter for sewage effluents. Water hyacinth plants are continuously subjected to contamination by mercury and other heavy metals from industrial effluents and fertilizer impurities. Little is known about the interaction of heavy metals/plants/insects. Aminotransferases are generally considered as indices for metabolic disturbances during Hg exposure. These enzymes are key enzymes for transamination, i.e., transfer of amino group from amino acid to keto acids which are ubiquitous in insects. The objective of the present study was to examine the bioaccumulation of mercury through the food chain in Neochetina eichhornae and its impact on protein metabolism.

Water hyacinth plants treated for a week with varying concentrations (10–50 ppm) of soluble Cd, Mn and Zn were taken and fed to the phytophagous weevils Neochetina eichhorniae (Warner), which were subsequently examined for the toxic effects and other parameters. These insects were processed for biochemical accumulation of metal ions and their effect on protein, DNA and RNA. Cd and Mn ions interfered with the protein synthesis as was evident with a lower value of RNA and DNA content compared to control, whereas zinc demonstrated the opposite effect i.e., increase in RNA and DNA content and also significant increase in protein synthesis. The possible mechanism of these variations are discussed in the light of the bioaccumulated metal ions in the living system.