Parity decreases methamphetamine-induced striatal dopaminergic perturbation

The role of parity upon methamphetamine-induced neurotoxicity of the striatal dopaminergic system was assessed. Female CD-1 mice either remained nulliparous or underwent one or three complete pregnancies and were designated as the 0, 1 or 3 pregnancy groups. The mice were then treated with a neurotoxic regimen of methamphetamine (MA - 40 mg/kg) or its saline vehicle (control) and striatal dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels were measured at 7-days post-MA. Basal levels of striatal DA, DOPAC and the DOPAC/DA ratio were similar among the saline (control) 0, 1 and 3 pregnancy groups. In response to MA, striatal DA and DOPAC were significantly decreased in the 0 and 1 pregnancy as compared with the control group. Mice with 3 pregnancies showed DA and DOPAC levels that did not differ from controls and were significantly greater than the 0 pregnancy group. The DOPAC/DA ratios of the 0 pregnancy group were significantly greater than all other groups (control, 1 and 3 pregnancy) which failed to differ among each other. These results demonstrate that parity decreases MA-induced striatal dopaminergic neurotoxicity, and the degree of this neuroprotection is related to the number of pregnancies experienced.     

Expression and biochemical characterization of two novel feruloyl esterases derived from fecal samples of Rusa unicolor and Equus burchelli

Two novel genes (tvms10a, tvmz2a) were identified in the metagenomic DNA of Rusa unicolor and Equus burchelli fecal samples. The amplified PCR product of tvms10a is composed of 917bp and the gene was found to encode a protein containing 165 amino acids, while the tvmz2a PCR product was 1053bp long encoding 298 amino acid proteins. The gene has 72% primary sequence identity with Clostridiales sp. These amplified PCR products which can encode FAE were cloned into pGEMT Easy TA cloning vector and then sub-cloned into the EcoRI site of pET32a expression vector to generate pET32-tvms10a and pET32-tvmz2a, which was then transformed into Escherichia coli BL21. The recombinants were grown in LB medium and gene expression was induced with IPTG for 6h. Purified recombinant Tvms10a and Tvmz2a proteins showed molecular masses of 18.6 and 31.2kDa respectively, and displayed hydrolytic activity towards substrate ethyl ferulate. The activities of Tvms10a and Tvmz2a produced in E. coli were 15 and 9U/min respectively, and their specific activities 16.6 and 10.4U/mg protein respectively. The optimal pH is between 5.0 and 8.0 and the optimal temperature is 37°C for enzyme reaction. Unusually, these proteins were found to be capable of releasing ferulic acid (FA) and diferulic acid (diFA) from untreated crude plant cell wall materials. The substrate utilization preferences and sequence similarity of these clones place it in the type-D sub-class of FAE.     

Functional alteration by NMDA antagonist: effects of L-Dopa,neuroleptics drug and postnatal administration

Summary.  Antiakinsic effects of the uncompetitive NMDA antagonists, memantine, amantadine and MK-801, and competitive antagonists, CGP 40116, alone or in co-administration with acute subthreshold dose of L-Dopa (5 mg/kg) in MPTP-treated mice, functional alterations induced by acute MK-801 in combinations with neuroleptic compounds or behavioural deficits following postnatal administration of MK-801 were investigated. Memantine and amantadine injected 60 min before the subthreshold dose of L-Dopa (5 mg/kg), induced antiakinesic actions in hypokinesic MPTP-treated mice. Concurrently, higher doses of memantine and MK-801 caused dyskinesic changes, reducing further rearing (10 and 30 mg/kg) and locomotor (30 mg/kg) behaviour of the MPTP mice; MK-801 elevated locomotion (0.1 mg/kg) but reduced rearing (0.3 mg/kg). In control, saline-treated mice, memantine (3, 10 and 30 mg/kg) and MK-801 (0.1 and 0.3 mg/kg) increased locomotor behaviour but decreased rearing behaviour. In rats, MK-801 induced marked increases in locomotor activity and disruptions of circular swim maze acquisition that were to greater or lesser extents blocked or potentiated by neuroleptic compounds: SCH 23390 (0.005 and 0.05 mg/kg) and clozapine (5.0 and 10.0 mg/kg) dose-dependently antagonised MK-801 (0.3 mg/kg) induced locomotor activity whereas raclopride (0.1 mg/kg) and haloperidol (0.1 mg/kg) attenuated it dose-specifically. Amperozide (0.5 mg/kg) attenuated the MK-801 effect but potentiated it at the 2.0 mg/kg dose. In the circular swim maze, raclopride (0.01 mg/kg) and SCH 23390 (0.05 mg/kg) improved the acquisitive performance of rats administered MK-801 (0.03 mg/kg) acutely whereas clozapine (10.0 mg/kg) and amperozide (2.0 mg/kg) deteriorated the performance of MK-801-treated rats. Postnatal administration of MK-801 (0.05 mg/kg, day 11 after birth) induced severe functional alterations in adult mice. At 70 days of age, MK-801 mice showed an initial hypoactivity followed by marked hyperactivity in the motor activity test chambers. These mice showed deficits in habituation, a nonassociative form of learning. Their hyperactivity in the test chambers was reversed by a low dose of d-amphetamine (0.25 mg/kg). Taken together, these findings display a wide range of acute/long-term functional alterations induced by NMDA antagonists, particularly MK-801, associated with animal models of brain disorders. Received July 9, 2001 Accepted August 6, 2001 Published online June 17, 2002     

A novel approach for removing an industrial dye 4GL by an Algerian Bentonite

Adsorption processes of 4GL on two different bentonite-based sorbents were compared: i) Sodium-bentonite in the presence of a cationic surfactant CTAMB; ii) organobentonite alone. This latter was prepared by exchanging the inorganic cation of bentonite with a quaternary ammonium cation at 100% of the clay's CEC. Batch adsorption studies were conducted to evaluate the effect of various parameters such as the quaternary ammonium cation (CTAMB) loading, contact time and initial 4GL concentration.From the kinetic study, it is interesting to note that Organobentonite exhibits faster kinetics compared to Na-bentonite/CTAMB system. The comparison between isotherm plots makes clear that the presence of CTAMB in solution changes the 4GL isotherm. Compared to organobentonite, the adsorption capacity is higher when CTAMB was present in solution. In this case, the results of 4GL adsorption by bentonite obey to Langmuir model. While for organobentonite, all models seem to be applicable. The difference between the two methods is confirmed by XRD analysis.The performance shown by Organobentonite and Na-bentonite/CTAMB system was suitable compared to other adsorbents, reflecting a promising future utilization in wastewater treatment.     

Quantitative comparison of carcinogenicity, mutagenicity and electrophilicity of 10 direct-acting alkylating agents and of the initial O6:7-alkylguanine ratio in DNA with carcinogenic potency in rodents

The quantitative relationship between carcinogenicity in rodents and mutagenicity in Salmonella typhimurium was examined, by using 10 monofunctional alkylating agents, including N-nitrosamides, alkyl methanesulfonates, epoxides, β-propiolactone and 1,3-propane sultone. The compounds were assayed for mutagenicity in two S. typhimurium strains (TA1535 and TA100) and in plate and liquid assays. The mutagenic activity of the agents was compared with their alkylating activity towards 4-(4′-nitrobenzyl)pyridine and with their half-lives (solvolysis constants) in an aqueous medium. No correlations between these variables were found, nor was mutagenic activity correlated with estimates of carcinogenicity in rodents.

There was a positive relationship between carcinogenicity and the initial ratios of 7-: O⁶-alkylguanine formed or expected after their reaction with double-stranded DNA in vitro. The results suggest that alkylation of guanine at position O⁶ (or at other O atoms of DNA bases) may be a critical DNA-base modification that determines the overall carcinogenicity of these alkylating agents in rodents.     

Assessment of changes in DNA methylation by methylation-sensitive amplification polymorphism in Jatropha curcas L. subjected to salinity stress

The present study assesses the changes in DNA methylation in leaf and root tissues of Jatropha curcas L., induced by salinity stress using methylation sensitive amplification polymorphism (MSAP) markers. Seedlings of 21 days (d) grown under controlled conditions were subjected to 0–100 mM salinity treatment for 24 h (1 d). Immediate changes in DNA methylation and polymorphism in methylated DNA in whole genome of both leaves and roots were assessed using 10 selective combinations of MSAP primers. In root and leaves 70.06% and 57.89% methylation was observed respectively. Similarly 67.22% and 71.21% polymorphism was observed in methylated DNA from root and leaf tissues respectively. Compared with control, the percentage of methylation and methylation polymorphism in roots of plants under different dosages of salinity was found in the order of 50 mM < 25 mM = 100 mM < 75 mM and 75 mM < 25 mM < 50 mM < 100 mM respectively. Similarly percentage of methylation and methylation polymorphism in leaves of plants treated with different levels of salinity was found in order of 75 mM < 25 mM < 50 mM < 100 mM and 50 mM < 25 mM < 100 mM < 75 mM respectively. The MSAP analysis showed that under salt stress homologous nucleotide sequences in genome from control and salt treated plants of J. curcas showed different patterns of methylation; which suggest that these fragments probably play an important role to induce immediate adaptive responses in Jatropha under salinity stress.     

Florida Red Tide Toxins (Brevetoxins) and Longitudinal Respiratory Effects in Asthmatics

Having demonstrated significant and persistent adverse changes in pulmonary function for asthmatics after 1 h exposure to brevetoxins in Florida red tide (Karenia brevis bloom) aerosols, we assessed the possible longer term health effects in asthmatics from intermittent environmental exposure to brevetoxins over 7 years. 125 asthmatic subjects were assessed for their pulmonary function and reported symptoms before and after 1 h of environmental exposure to Florida red tide aerosols for up to 11 studies over seven years. As a group, the asthmatics came to the studies with normal standardized percent predicted pulmonary function values. The 38 asthmatics who participated in only one exposure study were more reactive compared to the 36 asthmatics who participated in ≥4 exposure studies. The 36 asthmatics participating in ≥4 exposure studies demonstrated no significant change in their standardized percent predicted pre-exposure pulmonary function over the 7 years of the study. These results indicate that stable asthmatics living in areas with intermittent Florida red tides do not exhibit chronic respiratory effects from intermittent environmental exposure to aerosolized brevetoxins over a 7 year period.     

Quantitative subunit hybridization of drosophilaα-Glycerophosphate dehydrogenase

Summary The dimeric enzyme,mg src="/content/mg5v361761127140/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Glycerophosphate dehydrogenase, was purified from eight Drosophila species by the method of Collier et al. (1976). The enzymes were inactivated at high pH and the conditions sufficient for reactivation were established. Electrophoretic patterns of reactivatedmg src="/content/mg5v361761127140/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-glycerophosphate dehydrogenases which were mixed following inactivation of two species' enzymes, demonstrate that high pH dissociates the enzyme into its constituent subunits and reactivation involves subunit reassociation. Twenty interspecific combinations of dissociated enzymes were allowed to reassociate, and the amounts of both heterospecific and homospecific enzyme activity and protein were determined by densitometry. In all 20 tests there were no differences between observed and expected heterospecific:homospecific enzyme ratios. These results are consistent with the very slow rate of evolution of this enzyme in the family Drosophilidae (Collier and MacIntyre, 1977).