Protective Role of Lithium in Ameliorating the Aluminium-induced Oxidative Stress and Histological Changes in Rat Brain

This study was carried out to investigate the effects of lithium (Li) supplementation on aluminium (Al) induced changes in antioxidant defence system and histoarchitecture of cerebrum and cerebellum in rats. Al was administered in the form of aluminium chloride (100 mg/kg b.wt./day, orally) and Li was given in the form of Li carbonate through diet (1.1 g/kg diet, daily) for a period of 2 months. Al treatment significantly enhanced the levels of lipid peroxidation and reactive oxygen species in both the cerebrum and cerebellum, which however were decreased following Li supplementation. The enzyme activities of catalase, superoxide dismutase (SOD) and glutathione reductase (GR) were significantly increased in both the regions following Al treatment. Li administration to Al-fed rats decreased the SOD, catalase and GR enzyme activities in both the regions; however, in cerebellum the enzyme activities were decreased in comparison to normal controls also. Further, the specific activity of glutathione-s-transferase and the levels of total and oxidized glutathione were significantly decreased in cerebrum and cerebellum following Al treatment, which however showed elevation upon Li supplementation. The levels of reduced glutathione were significantly decreased in cerebrum but increased in cerebellum following Al treatment, which however were normalized upon Li supplementation but in cerebellum only. Apart from the biochemical changes, disorganization in the layers of cerebrum and vacuolar spaces were also observed following Al treatment indicating the structural damage. Similarly, the loss of purkinje cells was also evident in cerebellum. Li supplementation resulted in an appreciable improvement in the histoarchitecture of both the regions. Therefore, the study shows that Li has a potential to exhibit neuroprotective role in conditions of Al-induced oxidative stress and be explored further to be treated as a promising drug against neurotoxicity.     

Role of Ethylene in the Geotropic Response of Bermudagrass (Cynodon dactylon L. Pers.) Stolons

We studied the relationship between ethylene and gravity-induced upward bending of bermudagrass (Cynodon dactylon L. Pers.) stolons. Ethylene production begins within 3 hours of the onset of gravistimulation, and increases thereafter until the 15th hour, after which it declines. There is a close positive relationship between ethylene production and upward bending during the first 12 hours of gravistimulation. Incubation of stolons with AgNO₃ did not prevent ethylene evolution but delayed upward bending. In addition, ethylene production was 10-fold greater and peaked earlier in gravistimulated nodes incubated with 1-aminocyclopropane 1-carboxylic acid. The gravitational stimulation could be due to an increase in both 1-aminocyclopropane 1-carboxylic acid synthase and the ethylene forming enzyme. The results suggest that ethylene promotes the activity of indoleacetic acid.     

The small-scale pattern of Cynodon dactylon in Mediterranean pastures

The abundance of Cynodon dactylon was recorded in 50 plots presenting different geomorphological conditions and along a transect of 16 500 2×2 cm contiguous quadrats within a small basin 330 m in length, in the granite pediment of the Sierra de Guadarrama (Central Spain). Soil analyses were undertaken on samples from the 50 plots and the soil information matrix obtained was analysed using Principal Components Analysis and Discriminant Analysis. Results showed that in the Mediterranean pastures Cynodon dactylon was restricted to deep, well developed soils with relatively high values of cations, conductivity and organic matter, and could be used as an indicator of such soil conditions in these grasslands. The spatial pattern of the species was analysed using New Local Variances which revealed the existence of a small-scale pattern, ranging from 8 to 18 cm, present at all levels of the analysis. The size of small-scale patterns was positively correlated with species abundance and was interpreted as a relation between plant vigour and favourable soil conditions.I would like to thank Professor González Bernáldez for his interest and encouragement.     

Phyto-bioconversion of hard coal in the Cynodon dactylon/coal rhizosphere

Fundamental processes involved in the microbial degradation of coal and its derivatives have been well documented. A mutualistic interaction between plant roots and certain microorganisms to aid growth of plants such as Cynodon dactylon (Bermuda grass) on hard coal dumps has recently been suggested. In the present study coal bioconversion activity of nonmycorrhizal fungi was investigated in the C. dactylon/coal rhizosphere. Fungal growth on 2% Duff-agar, gutation formation on nitric acid treated coal and submerged culture activity in nitrogen-rich and -deficient broth formed part of the screening and selection of the fungi. The selected fungal isolates were confirmed to be found in pristine C. dactylon/coal rhizosphere. To simulate bioconversion, a fungal aliquot of this rhizosphere was used as inoculum for a Perfusate fixed bed bioreactor, packed with coal. The results demonstrate an enhanced coal bioconversion facilitated by low molecular weight organics and the bioconversion of coal may be initiated by an introduction of nitrogen moieties to the coal substrate. These findings suggest a phyto-bioconversion of hard coal involving plant and microbes occurring in the rhizosphere to promote the growth of C. dactylon. An understanding of this relationship can serve as a benchmark for coal dumps rehabilitation as well as for the industrial scale bioprocessing of hard coal.     

Malathion-induced Oxidative Stress in Rat Brain Regions

Malathion is a pesticide with high potential for human exposure. However, it is possible that during the malathion metabolism, there is generation of reactive oxygen species (ROS) and malathion may produce oxidative stress in intoxicated rats. The present study was therefore undertaken to determine malathion-induced lipid peroxidation (LPO), protein carbonylation and to determine whether malathion intoxication alters the antioxidant system in brain rats. Malathion was administered intraperitoneally in the acute and chronic protocols in the doses of 25, 50, 100 and 150 mg malathion/kg. The results showed that LPO in brain increased in both protocols. The increased oxidative stress resulted in an increased in the activity of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT), observed in cortex, striatum in the acute malathion protocol and hippocampus in the chronic malathion protocol. Our results demonstrated that malathion induced oxidative stress and modulated SOD and CAT activity in selective brain regions.     

Physiological integration enhanced the tolerance of Cynodon dactylon to flooding

Many flooding‐tolerant species are clonal plants; however, the effects of physiological integration on plant responses to flooding have received limited attention. We hypothesise that flooding can trigger changes in metabolism of carbohydrates and ROS (reactive oxygen species) in clonal plants, and that physiological integration can ameliorate the adverse effects of stress, subsequently restoring the growth of flooded ramets. In the present study, we conducted a factorial experiment combining flooding to apical ramets and stolon severing (preventing physiological integration) between apical and basal ramets of Cynodon dactylon, which is a stoloniferous perennial grass with considerable flooding tolerance. Flooding‐induced responses including decreased root biomass, accumulation of soluble sugar and starch, as well as increased activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX) in apical ramets. Physiological integration relieved growth inhibition, carbohydrate accumulation and induction of antioxidant enzyme activity in stressed ramets, as expected, without any observable cost in unstressed ramets. We speculate that relief of flooding stress in clonal plants may rely on oxidising power and electron acceptors transferred between ramets through physiological integration.     

不同地理种群狗牙根耐寒性研究

低温是狗牙根冬季生长的主要限制因素,越来越引起草业工作者的重视.以收集于我国不同地理种群的野生狗牙根为试验材料,探讨低温对不同种群狗牙根草坪质量和生理反应的影响,为抗寒栽培和耐冷育种提供理论和实践支持.结果表明:起源于高纬度狗牙根耐寒性最强,低纬度最差.起源纬度与狗牙根的耐寒性、可溶性糖含量、可溶性蛋白含量具有极显著的相关性,与过氧化氢酶(CAT)和过氧化物酶(POD)活性具有显著的相关性,而与草坪质量、超氧化物岐化酶(SOD)活性、丙二醛(MDA)含量、叶绿素a、叶绿素b以及叶绿素含量的相关性不显著.     

中国狗牙根(Cynodon dactylon)优良选系的RAPD分析

对采自中国不同地区的6份狗牙根[Cynodon dactylon (L.) Pers.]优良选系进行了RAPD分子标记实验.选用15个引物共扩增出438条带,平均每个引物扩增出29条带,其中多态性带415条,多态性位点百分率达到59.02%～75.49%.各选系间遗传相似性系数差异较大(0.408～0.672),说明各选系间在DNA水平上存在着丰富的遗传多样性,与新品种C106(爬地青)相比,各选系还存在一定的改良空间.实验结果也表明,RAPD分子标记可成功地用于中国狗牙根优良选系遗传多样性的研究及品种鉴定.     

Insulin Binding in Four Regions of the Developing Rat Brain

Specific insulin binding has been demonstrated in partially purified membranes prepared from four regions of the developing rat brain. Insulin binding to brain membranes demonstrated kinetics and hormonal specificity that were quite similar to those reported for traditional insulin target tissues (e.g., liver and adipose tissue), and binding was significantly correlated with receptor concentration. Binding in the olfactory bulbs, cerebrum, cerebellum, and hypothalamus all reached highest values at 15 days of postnatal life, with the olfactory bulbs generally showing the greatest binding at all ages studied. A temporal relationship was found between insulin binding to brain membranes in the postnatal rat and plasma membrane protein synthesis, especially in the cerebellum and olfactory bulbs.     

Chromosome Number in Cynodon dactylon in Relation to Ecological Conditions

Populations of Cynodon dactylon (L.) Pers. were collected fromthree habitat types (roadsides, lawns and paddy-fields) withineach of five climatic regions (arid, dry, intermediate, wetand hill country) in Sri Lanka. Further populations were collectedfrom forests and grasslands in the hill country. Most populations contained only tetraploid plants (2n = 36),but populations from roadsides and lawns in the wet region,and from forests in the hill country, contained only diploidplants (2n = 18). Populations from paddy-fields in the wet regioncontained both tetraploid and diploid plants. No triploid plantswere found in any environment, despite the fact that C. dactylonpredominantly reproduces vegetatively by both stolons and rhizomes.Soil acidity seems to be the main factor determining the distributionof the two cytotypes.Copyright 1995, 1999 Academic Press Cynodon dactylon (L.) Pers., chromosome number, ecology, habitat, climatic region     

Pyrroloquinoline Quinine Protects Rat Brain Cortex Against Acute Glutamate-Induced Neurotoxicity

To investigate possible protective effects of pyrroloquinoline quinone (PQQ) on the rat cortex with glutamate injection and to understand the mechanisms linking the in vivo neuroprotection of PQQ. Adult Sprague–Dawley rats received glutamate injection into the rat cortex. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling assay was performed to observe influences of co-treatment with PQQ (simultaneous injection with PQQ and glutamate) on neural cell apoptosis in the rat cortex. The production of reactive oxygen species (ROS) in the rat cortex was detected by flow cytometry using 2′,7′-dichlorofluorescin diacetate labeling, and the activity of superoxide dismutase, glutathione and malondialdehyde was respectively determined. Real time quantitative RT-PCR and Western blot were applied to measure the mRNA and protein expressions of Nrf1, Nrf2, HO-1 and GCLC in the rat cortex. Western blot was used to detect the phosphorylation of Akt and GSK3β in the rat cortex. Co-treatment with PQQ protected neural cells in the rat cortex from glutamate-induced apoptosis. PQQ decreased the ROS production induced by glutamate injection. PQQ increased the mRNA and protein expressions of Nrf2, HO-1 and GCLC and the phosphorylation of Akt and GSK3β in the cortex of glutamate-injected rats. PQQ could produce neuroprotective effects on the rat cortex. The antioxidant properties of PQQ and PQQ-induced activation of Akt/GSK3β signal pathway might be responsible for the in vivo neuroprotection of PQQ.     

Physiological responses of bermudagrass (Cynodon dactylon) to submergence

A split-plot design was used to study the physiological responses of anti-oxidative enzymes and carbohydrate contents of bermudagrass to different durations (0, 3, 7, 15, 30, 60, 90, 120 and 150 days) and depths of submergence (0, 1, 5 and 15 m). The results suggest that submergence caused a higher production of malondialdehyde and more significant changes in the different submerged treatments. The activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) in roots increased with the increase of the durations and depths of submergence, implying an integrated pathway involving CAT, SOD, POD, GR and APX for protection against the detrimental effects of activated oxygen species under submergence. Total soluble carbohydrate and starch contents of shoots and roots decreased with the increase of the depth and duration of submergence, but remained at relatively high level at the end of the study, showing quiescence is one of the major strategies of bermudagrass under the stress of submergence. The results suggest that bermudagrass can endure long-term and deep submergence by balancing between the formation and detoxification of activated oxygen species, lowering metabolism and reserving high amounts of carbohydrate.     

Difference in the Pattern of Soluble Proteins from Rat Brain Regions

The electrophoretic pattern of soluble proteins from seven rat brain regions (amygdala, cerebellum, corpus striatum, cortex, hypothalamus, medulla, and midbrain) was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Although the number of protein bands (36) was identical in all brain regions studied, there were differences in their relative densities, the greatest variation occurring in the low-molecular-weight region of the electrophoretogram. The bulk of the soluble proteins had molecular weights between 23,000 and 90,000 daltons. The medulla and amygdala showed the greatest range of protein band concentration. A large number of protein bands in the midbrain and corpus striatum showed a greater concentration of protein compared to the same bands in the other regions. A protein band that migrated with the same characteristic as albumin was found. It was consistently high in all regions, the midbrains showing a 1.5-fold greater concentration compared to other regions. Linear regression analysis of wet weight of regional brain tissue against protein concentration yielded a regression coefficient (r2) of 0.77. Midbrain and corpus striatum showed a relatively higher protein concentration: weight ratio than other regions.     

克隆整合有助于狗牙根抵御水淹

尽管国内外开展了大量的克隆整合对克隆植物抵御逆境能力影响的研究, 但整合对植物抵御水淹能力的影响研究仍比较缺乏。该文从克隆整合的角度探讨多年生草本植物狗牙根(Cynodon dactylon)对水淹胁迫的响应。试验模拟了先端分株(相对年幼的分株)分别处于0、5和15 cm三种水淹胁迫环境, 并在每个水淹梯度下实施先端分株与基端分株(相对年长的分株)之间匍匐茎连接或切断处理, 调查水淹一个月后基端分株和先端分株以及整个克隆片段在形态和生理上的表现。研究发现: 切断匍匐茎连接显著降低了狗牙根先端分株的生长, 表现在生物量下降、匍匐茎长度减短和分株数减少等方面; 水淹显著抑制了先端分株的生长, 但对基端分株的生长并未造成显著影响; 在5 cm水淹处理下, 匍匐茎保持连接时, 先端分株和整个克隆片段的生长显著增加; 连接或切断处理在不同水淹梯度下对匍匐茎平均节间长没有显著影响, 对先端分株或基端分株在光化学转化效率上也未表现显著性差异。结果表明: 克隆整合效应促进了狗牙根在水淹胁迫下分株的生长, 并有助于整个克隆片段抵御水淹胁迫。     

AFLP analysis of Cynodon dactylon (L.) Pers. var. dactylon genetic variation.

Cynodon dactylon (L.) Pers. var. dactylon (common bermudagrass) is geographically widely distributed between about lat 45 degrees N and lat 45 degrees S, penetrating to about lat 53 degrees N in Europe. The extensive variation of morphological and adaptive characteristics of the taxon is substantially documented, but information is lacking on DNA molecular variation in geographically disparate forms. Accordingly, this study was conducted to assess molecular genetic variation and genetic relatedness among 28 C. dactylon var. dactylon accessions originating from 11 countries on 4 continents (Africa, Asia, Australia, and Europe). A fluorescence-labeled amplified fragment length polymorphism (AFLP) DNA profiling method was used to detect the genetic diversity and relatedness. On the basis of 443 polymorphic AFLP fragments from 8 primer combinations, the accessions were grouped into clusters and subclusters associating with their geographic origins. Genetic similarity coefficients (SC) for the 28 accessions ranged from 0.53 to 0.98. Accessions originating from Africa, Australia, Asia, and Europe formed major groupings as indicated by cluster and principal coordinate analysis. Accessions from Australia and Asia, though separately clustered, were relatively closely related and most distantly related to accessions of European origin. African accessions formed two distant clusters and had the greatest variation in genetic relatedness relative to accessions from other geographic regions. Sampling the full extent of genetic variation in C. dactylon var. dactylon would require extensive germplasm collection in the major geographic regions of its distributional range.     

Acetylcholinesterase Activity in Regions of the Rat Brain Following a Convulsion

The effects of electroconvulsive shock on the levels of acetylcholinesterase in several brain regions of the rat were studied. Hippocampus, mesencephalon, cortex, and striatum exhibited rapid changes in acetylcholinesterase activity during the first few minutes following the convulsion, whereas brainstem and basal forebrain levels remained unchanged. In both hippocampus and midbrain there was a sustained decrease in activity: the total acetylcholinesterase activity was decreased by up to 40% within 2 min of the convulsion and did not return to control values for another 3 h. Thirty minutes after a flurothyl-induced convulsion there was a similar fall in acetylcholinesterase activity in both these regions, whereas a subconvulsive electric shock produced no change. It is concluded that a convulsion produces significant short-term decreases in acetylcholinesterase activity in areas of the rat brain that are involved in the generation and propagation of seizures, and the question is raised of whether this is related to the increase in seizure threshold that follows a convulsion.     

根癌农杆菌介导的金边狗牙根遗传转化条件的优化

为建立根癌农杆菌(Agrobacterium tumefaciens,菌(L.)Pers.]最佳遗传转化体系,以葡萄糖醛酸糖苷酶(GUS)基因的瞬间表达率为指标,从愈伤组织继代时间、根癌农杆菌侵染时间、负压条件及光照时间等方面进行了筛选.结果表明,根癌农杆菌介导的金边狗牙根最佳的转化体系是:以继代培养2周的愈伤组织为起始材料,根癌农杆菌介导感染10 min,经负压处理(抽拉20次)并在全光条件下共培养转化.     

Neuroprotective Effects of Baicalein on Acrolein-induced Neurotoxicity in the Nigrostriatal Dopaminergic System of Rat Brain

Elevated levels of acrolein, an α,β-unsaturated aldehyde are detected in the brain of patients with Parkinson’s disease (PD). In the present study, the neuroprotective effect of baicalein (a phenolic flavonoid in the dried root of Scutellaria baicalensis Georgi) on acrolein-induced neurodegeneration of nigrostriatal dopaminergic system was investigated using local infusion of acrolein in the substantia nigra (SN) of rat brain. Systemic administration of baicalein (30 mg/kg, i.p.) significantly attenuated acrolein-induced elevations in 4-hydroxy-2-noneal (a product of lipid peroxidation), N-(3-formyl-3,4-dehydropiperidino)lysine (a biomarker of acrolein-conjugated proteins), and heme-oxygenase-1 levels (a redox-regulated protein) in the infused SN, indicating that baicalein inhibited acrolein-induced oxidative stress and protein conjugation. Furthermore, baicalein reduced acrolein-induced elevations in glial fibrillary acidic protein (a biomarker of activated astrocytes), ED-1 (a biomarker of activated microglia), and mature cathepsin B levels (a cysteine lysosomal protease), suggesting that baicalein attenuated acrolein-induced neuroinflammation. Moreover, baicalein attenuated acrolein-induced caspase 1 activation (a pro-inflammatory caspase) and interleukin-1β levels, indicating that baicalein prevented acrolein-induced inflammasome activation. In addition, baicalein significantly attenuated acrolein-induced caspase 3 activation (a biomarker of apoptosis) as well as acrolein-induced elevation in receptor interacting protein kinase (RIPK) 3 levels (an initiator of necroptosis), indicating that baicalein attenuated apoptosis and necroptosis. At the same time, baicalein mitigated acrolein-induced reduction in dopamine levels in the striatum ipsilateral to acrolein-infused SN. In conclusion, our data suggest that baicalein is neuroprotective via inhibiting oxidative stress, protein conjugation, and inflammation. Furthermore, baicalein prevents acrolein-induced program cell deaths, suggesting that baicalein is therapeutically useful for slowing PD progression.     

Functional dissection of drought-responsive gene expression patterns in Cynodon dactylon L.

Water deficit is one of the main abiotic factors that affect plant productivity in subtropical regions. To identify genes induced during the water stress response in Bermudagrass (Cynodon dactylon), cDNA macroarrays were used. The macroarray analysis identified 189 drought-responsive candidate genes from C. dactylon, of which 120 were up-regulated and 69 were down-regulated. The candidate genes were classified into seven groups by cluster analysis of expression levels across two intensities and three durations of imposed stress. Annotation using BLASTX suggested that up-regulated genes may be involved in proline biosynthesis, signal transduction pathways, protein repair systems, and removal of toxins, while down-regulated genes were mostly related to basic plant metabolism such as photosynthesis and glycolysis. The functional classification of gene ontology (GO) was consistent with the BLASTX results, also suggesting some crosstalk between abiotic and biotic stress. Comparative analysis of cis-regulatory elements from the candidate genes implicated specific elements in drought response in Bermudagrass. Although only a subset of genes was studied, Bermudagrass shared many drought-responsive genes and cis-regulatory elements with other botanical models, supporting a strategy of cross-taxon application of drought-responsive genes, regulatory cues, and physiological-genetic information.