Experimental and computational studies on the binding of diazinon to human serum albumin

In the present research, the binding properties of diazinon (DZN), as an organophosphorus herbicide, to human serum albumin (HSA) were investigated using combination of spectroscopic, electrochemistry, and molecular modeling techniques. Changes in the UV–Vis and FT-IR spectra were observed upon ligand binding along with a significant degree of tryptophan fluorescence quenching on complex formation. The obtained results from spectroscopic and electrochemistry experiments along with the computational studies suggest that DZN binds to residues located in subdomains IIA of HSA with binding constant about 1410.9 M^?1 at 300 K. From the thermodynamic parameters calculated according to the van’t Hoff equation, the enthalpy change ΔH° and entropy change ΔS° were found to be ?16.695 and 0.116 KJ/mol K, respectively. The primary binding pattern is determined by hydrophobic interaction and hydrogen binding occurring in so-called site I of HSA. DZN could slightly alter the secondary structure of HSA. All of experimental results are supported by computational techniques such as docking and molecular dynamics simulation using a HSA crystal model.     

Kinetic constants for the inhibition of camel retinal acetylcholinesterase by the carbamate insecticide lannate

We have designed this study to determine various kinetic parameters of camel retinal membrane‐bound acetylcholinesterase (AChE; EC 3.1.1.7) inhibition by carbamate insecticide lannate [methyl N‐{{(methylamino)carbonyl}oxy} ethanimidothioate]. All these kinetic constants were derived by simple graphical methods. The value of kinetic parameters was estimated as follows: 0.061 (μM)⁻¹, 1.14 (μM)⁻¹, 0.216 μM, 0.016 min⁻¹, 0.0741 (μM min)⁻¹, 0.746 μM, and 4.42 μM for velocity constant (K_v), new inhibition constant (K_nic), dissociation constant (K_d), carbamylation rate constant (k_2c), overall carbamylation rate constant (k′2 ), 50% inhibition constant (K_I50), and 99% inhibition constant (K_I99), respectively. These unique methods may be used to estimate such kinetic parameters for time‐dependent inhibition of enzymes by variety of chemicals, insecticides, herbicides, and drugs. © 1998 John Wiley & Sons, Inc. J Biochem Toxicol 13: 41–46, 1999     

The ecological integrity of the lower Olifants River,Limpopo province,South Africa: 2009–2015 – Part B: Tributaries of the Olifants River

Monitoring on the Lowveld reaches of the Olifants River, Limpopo River System, and its Steelpoort, Blyde, Klaserie and Selati tributaries was initiated in 2009. Analysis of the 2009–2015 data from four Olifants River sites showed deterioration in the river’s ecological condition between where it enters the Lowveld and where it enters the Kruger National Park, with a slight recovery within the Kruger National Park. Physico-chemical, aquatic macroinvertebrate and fish data collected in 2009–2015 at six sites on the Steelpoort, Blyde, Klaserie and Selati tributaries of the Olifants River corroborated the ecological condition of these tributaries. The Selati was the most polluted and was in a critically modified condition, whereas the Klaserie and Steelpoort were in fair condition and the Blyde was in good condition. The Selati appeared to have a significant negative impact on the water quality, macroinvertebrates and fish of the Olifants River within the Kruger National Park.     

Human health risks of metals and metalloids in muscle tissue of Synodontis zambezensis Peters, 1852 from Flag Boshielo Dam,South Africa

Muscle tissue from 63 Synodontis zambezensis collected bimonthly in 2013 at Flag Boshielo Dam were analysed for metals and metalloids in a desktop human health risk assessment. The Hazard Quotient, based on a weekly meal of 67 g of fish muscle, exceeded the maximum acceptable level of one for lead, cobalt, cadmium, mercury, arsenic and selenium. The concentrations of these elements were higher in 2013 than those recorded in 2009 and 2012 in other fish species from Flag Boshielo Dam and these may pose a long-term health risk if consumed regularly by impoverished rural communities reliant on fish as a source of protein.     

Taste attractiveness of free amino acids for juveniles of Persian sturgeon <Emphasis Type="Italic">Acipenser persicus</Emphasis>

Taste preferences towards 20 free amino acids (L-isomers, 0.1–0.0001 M) were determined in juveniles of Persian sturgeon Acipenser persicus. It was found that most amino acids (16) had a positive effect on extraoral gustatory reception (increased the frequency of catching artificial pellets by fishes). The most efficient amino acids were the following: threonine, histidine, arginine, asparagine, phenylalanine, cysteine, glutamine, and glycine. Fifteen amino acids were efficient for intraoral gustatory receptors: serine, arginine, cysteine, histidine, alanine, and some others. The presence of these amino acids in pellets increased the consumption. Amino acids decreasing the frequency of catching or consumption of pellets were not found. Highly significant positive correlation was found between the amino acid ranges mediated by the extraoral and intraoral gustatory reception. The fishes demonstrated maximum sensitivity to aspartic acid, 0.01 and 0.001 M, respectively, for intraoral and extraoral gustatory systems. The threshold concentrations of arginine and glycine were higher for the intraoral gustatory system (0.01 M) than for the extraoral one (0.1 M). The comparison of Persian sturgeon with sturgeon fishes (Russian sturgeon A. gueldenstaedtii, Siberian sturgeon A, baerii, and starred sturgeon A. stellatus) studied earlier confirmed high species specificity of intraoral taste preferences in representatives of Acipenser genus. Species specificity of extraoral taste ranges was less pronounced.     

Comparison of Beta-value and M-value methods for quantifying methylation levels by microarray analysis

Background  

High-throughput profiling of DNA methylation status of CpG islands is crucial to understand the epigenetic regulation of genes. The microarray-based Infinium methylation assay by Illumina is one platform for low-cost high-throughput methylation profiling. Both Beta-value and M-value statistics have been used as metrics to measure methylation levels. However, there are no detailed studies of their relations and their strengths and limitations.     

Intraperitoneal Aminoguanidine Improves Sciatic Nerve Ischemia–Reperfusion Injury in Male Sprague-Dawley Rats

The present work was designed to investigate the potential protective effects of post-ischemic treatment with aminoguanidine (AG) on sciatic nerve ischemia/reperfusion (I/R) injury in rat. Seventy-two rats were divided into 12 groups (n = 6). We used ischemia model in these groups by occluding the right common iliac and femoral arteries for 3 h with a silk suture 6-0 using slipknot technique. Treatment groups (2, 4, 6, 8, 10, and 12) received 150 mg/kg AG intraperitoneally 24 h after induction of ischemia. After certain time intervals of reperfusion (2, 4, 7, 14, and 28 days), the function of the hind limb was assessed using behavioral scores based on gait, racing reflex, toe spread, pinch sensitivity, paw position, and grasp. After euthanasia, sciatic nerves were removed at the end of reperfusion times and sections were cut at 5 μm, then were stained for light microscopy studies and graded for ischemic fiber degeneration (IFD), edema, and apoptosis. Maximal behavioral deficit occurred at 7 days of reperfusion. The comparison of behavioral score pertaining to the control and AG groups revealed significant differences and showed also a better time course in recovery (P < 0.05). Other than 3 and 4 groups, the amount of edema in AG treatment groups showed significant differences compared with control groups (P < 0.05). IFD was also significantly decreased in the AG treatment groups than controls. Most importantly, I/R-induced apoptosis were improved significantly on the 4th, 7^th, and 14th days of reperfusion in AG-treated groups compared to controls. In conclusion, our findings suggest that post-ischemic administration of AG exhibits protective effect against sciatic nerve I/R injury.     

Aminoguanidine Changes Hippocampal Expression of Apoptosis-Related Genes,Improves Passive Avoidance Learning and Memory in Streptozotocin-Induced Diabetic Rats

Cognitive dysfunction occurs in patients with diabetes mellitus. The objective of this study was to examine whether bilateral intrahippocampal CA1 (intra-CA1) injection of aminoguanidine (AG) can either affect the Bcl-2 family gene expression or reduce the diabetic imposing abnormalities of passive avoidance learning (PAL) and memory. Rats were divided into five groups: control (C), control treated with normal saline (CS), control treated with AG (S-AG), diabetics (D), and diabetics treated with AG (D-AG). Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (STZ) (50 mg/kg). AG (30 μg/rat) or vehicle was administered intra-CA1 bilaterally at the onset of hyperglycemia. PAL was assessed 7 weeks later. Animals were killed, and hippocampus was dissected following the behavioral test. The expressions of Bax, Bcl-2, and Bcl-xl mRNAs were measured using semiquantitative RT-PCR technique. The result of passive avoidance task showed that AG significantly improved the cognitive performance in diabetic rats. Moreover, AG treatment decreased the levels of Bcl-2 and Bcl-x_L expressions in diabetic group. The ratio of Bax/Bcl-2 and Bax/Bcl-x_L decreased significantly in AG-treated diabetic animals. In conclusion, initial treatment with AG by intra-CA1 micro-injection improves the impaired passive avoidance task in STZ-induced diabetic rats which may be related to the decreased Bax/Bcl-2 and Bax/Bcl-x_L ratios.     

Assessment of pharmacological activities of two medicinal plant of Bangladesh: Launaea sarmentosa and Aegialitis rotundifolia roxb in the management of pain,pyrexia and inflammation

Background

The current study aims at evaluating the analgesic, anti-pyretic and anti-inflammatory properties of methanolic extract of the stem, bark and leaves of Launaea sarmentosa and Aegialitis rotundifolia roxb.

Results

The AELS and AEAR extract presented a significant (***p < 0.001) dose dependent increase in reaction time in writhing method and showed inhibition of 63.1% and 57.1% respectively at the doses of 400 mg/kg body weight while standard drug showed (P < 0.001) inhibition of 69.23%. In tail immersion method, AELS and AEAR showed maximum time of tail retention at 30 min in hot water i.e. 6.93 sec and 6.54 sec respectively at highest doses of 400 mg/kg body weight than lower dose while standard pentazocine showed reaction time of 7.62 sec. The AELS and AEAR extract also exhibited promising anti-inflammatory effect as demonstrated by statistically significant inhibition of paw volume by 32.48% and 26.75% respectively at the dose of 400 mg/kg body weight while the value at the dose of 200 mg/kg body weight were linear to higher dose at the 3^rd hour of study. On the other hand, Standard indomethacin inhibited 40.13% of inflammation (***P < 0.001). In Cotton-pellet granuloma method, AELS and AEAR extract at the dose of 400 mg/kg body weight exhibited inhibition of inflammation of 34.7% and 29.1% respectively while standard drug showed (P < 0.001) inhibition of 63.22%. Intraperitoneal administration of AELS and AEAR showed dose dependent decrease in body temperature in brewer’s yeast induced hyperthermia in rats at both doses. However, AELS significantly decreased body temperature (***p < 0.001) at 400 mg/kg compared to control.

Conclusions

Present work propose that the methanolic extract of Launaea sarmentosa and Aegialitis rotundifolia roxb possesses dose dependent pharmacological action which supports its therapeutic use in folk medicine possibly mediated through the inhibition or blocking of release of prostaglandin and/or actions of vasoactive substances such as histamine, serotonin and kinins.