Chronic Manganese Treatment of Rats Alters Synaptosomal Uptake of Dopamine and the Behavioural Response to Amphetamine Administration

Abstract: Chronic manganese treatment from conception onward resulted in increased striatal synaptosomal uptake of dopamine, but not of a variety of other neurotransmitters/precursors in 80-day-old rats. The open-field behaviour of these manganese-treated 80-day-old rats was no different from that of untreated age-matched rats. However, amphetamine administration (1 mg/kg body weight) increased activity to a significantly lower extent in manganese-treated rats. These observations indicate that chronic manganese treatment results in marked alterations of activities associated with the dopaminergic system.     

The stability of electron transport in in vitro chloroplast membranes

The stability and stabilization of the electron transport system of chloroplast membranes under physiological conditions of temperature and illumination were studied in relation to two separate and often competing mechanisms of decay. Photochemical inactivation (photoinhibition) of the electron transport system of ageing spinach chloroplasts was not normally found to limit stability even at saturating light intensities. Only when the membranes were protected from dark (fatty acid) inhibition did photoinhibition limit stability.Electron transport could be partially protected from dark inhibition by the addition of high concentrations of recrystallized (i.e. fatty acid free) bovine serum albumin, ovalbumin, polyethyleneimine cellulose, Biomesh SM2 beads or with Ficoll 400. Some improvement in stability was achieved with N,N, dimethylphenethylamine but other esterase and phospholipase inhibitors were ineffective in preventing thermal inactivation.Photoinhibition was apparently delayed by phenazine methosulphate under certain conditions but was unaffected either by artificial scavengers of reactive oxygen species (butylated hydroxytoluene), and 1,4-diazobycyclo (2, 2, 2 octane) or by natural scavengers which constitute part of the in vivo protective mechanism (-tocopherol, -carotene, SOD, catalase and glutathione) or by anaerobic incubation. Photoinhibition may therefore be by a separate mechanism which does not initially involve free radical damage.Abbreviations BHA butylated hydroxyanisole - SOD superoxide dismutase - 0₃ ⁷ superoxide anion - 0₁ ² singlet molecular oxygen - MDA malondialdehyde - BHT butylated hydroxytoluene - DABCO 1,4-diazobicyclo (2, 2, 2) octane - PMS phenazine methosulphate - BSA bovine serum albumin - photosystem I, (II) PSI (PSII) - DMSO Dimethyl Sulphoxide - DCPIP 2,6, dichlorophenol indophenol - DBM1B 2,5, dibromo-3-methyl-6-isopropyl-p-benzoquinone     

Influence of aluminum in nutrient solutions on chemical composition in upland rice cultivars

Summary Aluminum toxicity is an important growth limiting factor for upland rice production on oxisols of cerrado region in Brazil. Data related to the effect of Al on uptake of nutrients for rice crop are limited. The effect of five Al concentrations (0, 10, 20, 40 and 60 ppm) in culture solution on the chemical composition of 30 upland rice cultivars was studied.Aluminum concentration and content in plant tissues were increased with higher levels of Al in all cultivar. In the roots Al content was higher as compared with the tops. Critical toxic level of Al in the tops of 21 days old plants varied from 100 to 417 ppm depending on the cultivars. Rice cultivars responded differently to Al treatments with respect to nutrients uptake. Increased Al concentrations in the solution exerted an inhibiting effect on the concentrations and contents of N, P, K, Ca, Mg, S, Na, Zn, Fe, Mn, B and Cu. Thus the inhibition was more effective for macronutrients in the plant tops in following order: Mg>Ca>P>K>N>S>Na. Whereas for micronutrients it was in the order of Mn>Zn>Fe>Cu>B. Morphological, physiological and biochemical effects of Al, toxicity responsible for the reduction in plant nutrient uptake, are discussed.     

Effects of aluminium on nodulation of two Stylosanthes species grown in nutrient solution

Summary Effects of three solution aluminium concentrations (0, 25 and 100 M) on nodulation ofStylosanthes hamata andStylosanthes scabra inoculated with Rhizobium CB 756 were studied using nutrient solution culture. Aluminium strongly affected nodulation by delaying nodule appearance and reducing the number and dry weight of nodules in both species. The effects of aluminium toxicity on nodulation were more pronounced inStylosanthes scabra than inStylosanthes hamata. These effects of aluminium on nodulation occurred before any significant effect of aluminium on top growth, root growth or root elongation. A plant transfer experiment suggested that aluminium interfered with root infection and/or nodule initiation in both species. The detrimental effect of aluminium on nodulation appeared to be associated with a reduction in lateral root density, thus decreasing the potential number of sites for root infection and nodule formation.     

Spirulina ameliorates arsenic induced reproductive toxicity in male rats

Spirulina (Spirulina platensis), has numerous health benefits including antioxidant, immunomodulatory, and anti-inflammatory activities, works against heavy metal toxicity, and is often used as a food supplement in human, animals, birds and fishes. This study aimed to evaluate the protective ability of the dietary spirulina against the toxic effects of inorganic arsenic (iAs) on male reproductive parameters in rats. Seventy-two mature Long-Evans male rats, dividing into six groups (T0, T1, T2, T3, T4 and T5) (12 rats/group) were included in this study. The T3, T4 and T5 group rats were treated with three consecutive doses (1.0 g, 1.5 g and 2.0 g/kg feed) of spirulina in feed along with 3.0 mg NaAsO₂/kg body weight (BW) in drinking water (DW) daily for 90 days. Each rat of group T1 received NaAsO₂ (3.0 mg/kg BW) in DW, and those of T2 group were fed with spirulina (2.0 g/kg feed) daily for 90 days. The rats of group T0 served as the control with normal feed and water. Total arsenic (tAs) contents, reproductive parameters (testicular weight, sperm motility and morphology), and histological changes in the testicles were evaluated in these rats. Arsenic dosing significantly (p=0.003, Kruskal-Wallis test) increased the tAs contents in the testicles, decreased testes weight, sperm morphology and motility compared to the controls. The effect of arsenic dosing was also evidenced by the histological changes like decreased germinal layers in the seminiferous tubules of the treated rats. Moreover, dietary spirulina (2.0 g/kg feed) supplementation significantly (p=0.011, Kruskal-Wallis test) lowered tAs contents in testicles and increases testes weights, sperm motility and morphology. Therefore, spirulina can be used as an effective dietary supplement to ameliorate the adverse effects of arsenic induced reproductive toxicities. However, further study is required to elucidate the underlying molecular mechanisms of reduction of arsenic induced reproductive toxicity by spirulina.     

In vivo assessment of reversing Cisplatin-Induced nephrotoxicity using Jatropha mollissima crude extract and its potential cytotoxicity

Jatropha mollissima is one of the ancient plants that known in Africa, Asia and Latin America for its high medicinal value. Previously we showed that the ethanolic leaves extract of J. mollissima was able to reverse the aminoglycoside antibiotics induced nephrotoxicity in only two weeks of administration. Here, we evaluated the phytochemicals, antioxidant and in vivo cytotoxicity of the ethanolic leaves extract in addition to the ability of reversing Cisplatin-induced nephrotoxicity in wistar albino rats. The results of phytochemical analysis showed the presence of flavonoids, phenols, tannins and saponins, with significantly high antioxidant activity. The treated rats did not show any cytotoxic signs; no anatomical, physiological and/or histopathological changes compared with the control group. Kidney, spleen and liver tissues appeared normal after two weeks administration of the maximum dose, with a possible alteration in distal tubules, proximal tubules and glomerulus of the kidney tissues. The results of nephrotoxicity and kidney function suggest promising potential for J. mollissima in kidney damage treatment.     

杀虫剂敌敌畏和除草剂丁草胺对饰纹姬蛙蝌蚪的急性毒性实验

采用静态换水法研究了杀虫剂敌敌畏、除草剂丁草胺对饰纹姬蛙(Microhyla ornata)蝌蚪的急性毒性影响。结果表明,杀虫剂敌敌畏对饰纹姬蛙蝌蚪的24-h、48-h的半致死浓度(LC50)分别为3．91μl／l和1．97μ/l;除草剂丁草胺对饰纹姬蛙蝌蚪的24-h LC50和48-h LC50分别为3．37μl／1和1．88μl／1,饰纹姬蛙蝌蚪对丁草胺的敏感性稍大于敌敌畏。     

Interactions of radiofrequency radiation-induced hyperthermia and 2-methoxyethanol teratogenicity in rats

Radiofrequency (RF) radiation is used in a variety of workplaces. In addition to RF radiation, many workers are concurrently exposed to numerous chemicals; exposed workers include those involved with the microelectronics industry, plastic sealers, and electrosurgical units. The developmental toxicity of RF radiation is associated with the degree and duration of hyperthermia induced by the exposure. Previous animal research indicates that hyperthermia induced by an elevation in ambient temperature can potentiate the toxicity and teratogenicity of some chemical agents. We previously demonstrated that combined exposure to RF radiation (10 MHz) and the industrial solvent, 2-methoxyethanol (2ME), produces enhanced teratogenicity in rats. The purpose of the present research is to determine the effects of varying the degree and duration of hyperthermia induced by RF radiation (sufficient to maintain colonic temperatures at control [38.5], 39.0, 40.0, or 41.0 °C for up to 6 h) and 2ME (100 mg/kg) administered on gestation day 13 of rats. Focusing on characterizing the dose-response pattern of interactions, this research seeks to determine the lowest interactive effect level. Day 20 fetuses were examined for external and skeletal malformations. The results are consistent with previous observations. Significant interactions were observed between 2ME and RF radiation sufficient to maintain colonic temperatures at 41 °C for 1 h, but no consistent interactions were seen at lower temperatures even with longer durations. These data indicate that combined exposure effects should be considered when developing both RF radiation and chemical exposure guidelines and intervention strategies. Bioelectromagnetics 18:349–359, 1997. © 1997 Wiley-Liss, Inc.     

Isatis phytogenic relieved atrazine induced growth retardation,hepato-renal dysfunction,and oxidative stress in Nile tilapia

The influence of herbicides causes health and economic loss, which requires innovative solutions to sustain the aquaculture industry. In this regard, dietary isatis is included in Nile tilapia diets to relieve atrazine (ATZ)-induced growth retardation, hepato-renal dysfunction, and oxidative stress. The first and second groups offered the control diet (control), while the third and fourth groups offered the isatis supplemented diet (1%). Meantime, half of the water was replaced and mixed with ATZ (1.39 mg/L) in the second and fourth groups for 30 days. The group of fish delivered isatis had significantly enhanced FBW, WG, and SGR, while fish intoxicated with ATZ had meaningfully impaired growth behavior (p < 0.05). Further, the FCR was improved by isatis, and ATZ resulted in the worst FCR among the groups. Interestingly fish fed isatis and exposed with ATZ (88.89%) had a higher survival rate than fish exposed with ATZ without isatis feeding, and both are lower than the control (97.78%) (p < 0.05). The histological structure in the isatis-treated groups showed distinguished enhancement and branching of the intestinal villi. The intestine of ATZ–treated fish revealed damage and inflammatory cell infiltration in the intestinal mucosa with separation of lining epithelium. Generally, fish fed isatis and intoxicated with ATZ had lower uric acid, urea, creatinine, ALT, and AST and higher total protein, globulin, and albumin than fish exposed with ATZ without feeding with isatis (p < 0.05). Markedly, fish-fed isatis had the highest SOD, CAT, GPx, and the lowest MDA level compared to the other groups (p < 0.05). Meanwhile, fish exposed with ATZ had the worst SOD, CAT, GPx, and the highest MDA level compared to the other groups (p < 0.05). In summary, dietary isatis relieved ATZ induced growth retardation, hepato-renal dysfunction, and oxidative stress in Nile tilapia.     

Effects of cadmium on growth of Helianthus annuus seedlings: physiological aspects

Sunflower seedlings ( Helianthus annuus hybrid Select) were grown in a complete nutrient solution in the absence or presence of Cd²⁺ (10 and 20 μM). Analyses were performed to establish whether there was a differential effect of Cd²⁺ on mature and young leaves. After 7 d the growth parameters as well as the leaf area had decreased in both mature and young leaves. Accumulation of Cd²⁺ in the roots exceeded that in the shoots. Seedlings treated with Cd²⁺ exhibited reduced contents of chlorophyll and CO₂ assimilation rate, with a greater decrease in young leaves. The photochemical efficiency of photosystem II (PSII) was not altered by Cd²⁺ treatment in either mature or young leaves, although during steady-state photosynthesis in young leaves there was a significant alteration in the following parameters: quantum yield of electron transport by PSII (Φ_PSII), photochemical quenching ( q _P), non-photochemical quenching ( q _NP), and excitation capture efficiency of PSII (Φ_exc).