Binding of dantrolene-Na to the ciliated membrane ofParamecium aurelia

Summary Dantrolene-Na is a muscular relaxant which binds to sarcoplasmic reticulum (SR) with high affinity and decreases the availability of Ca²⁺ channels. The binding of fluorescent compounds, dantrolene-Na, nifedipine and chlortetracycline to the ciliary membrane ofParamecium aurelia has been studied. Dantrolene at the concentrations of 1.9 · 10^–5, 3.8 · 10^–5 and 7.9 · 10^–5 M manifested a punctuated binding pattern to the cell membrane. Isolated cilia also bound dantrolene at their basal portion, whereas deciliated cell bodies lost their dotted binding pattern. Chlortetracycline showed a similar but weaker fluorescent staining. Nifedipine treated cells revealed no sign of fluorescent binding to the membrane and was only taken up in food vacuoles.Based on these observations we propose that dantrolene binding regular arrays ofParamecium cell membrane could be identical to granular plaques observed by electron microscope. The possible functioning of these structures as Ca²⁺ reservoirs is also discussed.     

Flow injection assays for NADH and ethanol using photosensitized rose bengal and luminol–copper (II) chemiluminescence system

The online photoreaction of the rose bengal photosensitized luminol–copper (II) chemiluminescence (CL) system was used for the determination of β-nicotinamide adenine dinucleotide (NADH) and ethanol (EtOH) in pharmaceutical formulations combined with a flow injection technique. NADH can significantly enhance the CL emission of the reaction. For EtOH, alcohol dehydrogenase in soluble form was utilized in the presence of nicotinamide adenine dinucleotide resulting in NADH production. The limit of detection (3σ blank, 𝑛 = 3) of 4.0 × 10⁻⁸ and 2.17 × 10⁻⁵ M, and linear range 1.3 × 10⁻⁷ to 2.5 × 10⁻⁵ M (R² = 0.9998, n = 6) and 0.11–2.17 × 10⁻³ M (R² = 0.9996, n = 6) were obtained for NADH and EtOH respectively. The injection rate was 100 h⁻¹ with a relative standard deviation (n = 3) of 1.5–4.8% in the range studied for both analytes. The procedure was satisfactorily applied to pharmaceutical formulations with recoveries in the range 91.6 ± 3.0% to 110 ± 2.0% for NADH and 88 ± 3.0% to 95.4 ± 4.0% for EtOH. The results obtained were very consistent and did not differ considerably from the reported approaches at a 95% confidence limit. The possible mechanism of the CL reaction is also explained briefly.     

Homology Modeling and Molecular Docking Studies of Glutamate Dehydrogenase (GDH) from Cyanobacterium Synechocystis sp. PCC 6803

Glutamate dehydrogenase (GDH), which is present in most bacteria and eukaryotes’ mitochondria, plays an important role in amino acid metabolism. In g     

Quantification of biochemical compounds in Bauhinia Variegata Linn flower extract and its hepatoprotective effect

Liver disorders may occur as a result of exposure to chemical compounds capable of inducing the oxidative stress and hepatic injuries. The aim of present study was to investigate the effects of flower extracts of B. Variegata for the treatment of liver injury induced by the CCl₄. About 1 ml/kg body weight (b.w) of CCl4 was induced to experimental mice by intraperitoneal way for 14 days. The methanol and chloroform extracts (100, 200 and 300 mg/kg b.w) were administered to experimental animals for 14 days along with standard drug Silymarine (100 mg/kg b.w). The extracts alone showed no evidence of hepatic toxicity but animals exposed to CCl₄ without the treatment with B. Variegata presented variations in levels of liver enzymes, antioxidant enzymes, proteins and blood cells as well as injuries in liver cells were also observed during histopathological study. However, after the treatments especially with 300 mg/kg b.w of methanol flower extracts levels of liver markers (ALT, AST and ALP), antioxidant enzymes and blood cells decreases and turned towards normal levels. Whereas level of total proteins and bilirubin was improved and damaged liver cells were repaired. The curative activity of flower extracts can be correlated to the higher potential of antioxidants and occurrence of Quercetin and some other organic compounds those were investigated from flower extracts of B. Variegata during HPLC and GC-MS analysis. The finding of this study supports the use of B. Variegata flower formulation in folk medicines.     

Genome-wide analysis of key salinity-tolerance transporter (HKT1;5) in wheat and wild wheat relatives (A and D genomes)

Exclusion of sodium ions from cells is one of the key salinity tolerance mechanisms in plants. The high-affinity cation transporter (HKT1;5) is located in the plasma membrane of the xylem, excluding Na⁺ from the parenchyma cells to reduce Na⁺ concentration. The regulatory mechanism and exact functions of HKT genes from different genotypic backgrounds are relatively obscure. In this study, the expression patterns of HKT1;5 in A and D genomes of wheat were investigated in root and leaf tissues of wild and domesticated genotypes using real-time PCR. In parallel, the K⁺/Na⁺ ratio was measured in salt-tolerant and salt-sensitive cultivars. Promoter analysis were applied to shed light on underlying regulatory mechanism of the HKT1;5 expression. Gene isolation and qPCR confirmed the expression of HKT1;5 in the A and D genomes of wheat ancestors (Triticum boeoticum, AbAb and Aegilops crassa, MMDD, respectively). Interestingly, earlier expression of HKT1;5 was detected in leaves compared with roots in response to salt stress. In addition, the salt-tolerant genotypes expressed HKT1;5 before salt-sensitive genotypes. Our results suggest that HKT1;5 expression follows a tissue- and genotype-specific pattern. The highest level of HKT1;5 expression was observed in the leaves of Aegilops, 6 h after being subjected to high salt stress (200 mM). Overall, the D genome allele (HKT1;5-D) showed higher expression than the A genome (HKT1;5-A) allele when subjected to a high NaCl level. We suggest that the D genome is more effective regarding Na⁺ exclusion. Furthermore, in silico promoter analysis showed that TaHKT1;5 genes harbor jasmonic acid response elements.     

How the Nucleus and Mitochondria Communicate in Energy Production During Stress: Nuclear MtATP6, an Early-Stress Responsive Gene, Regulates the Mitochondrial F1F0-ATP Synthase Complex

A small number of stress-responsive genes, such as those of the mitochondrial F₁F₀-ATP synthase complex, are encoded by both the nucleus and mitochondria. The regulatory mechanism of these joint products is mysterious. The expression of 6-kDa subunit (MtATP6), a relatively uncharacterized nucleus-encoded subunit of F₀ part, was measured during salinity stress in salt-tolerant and salt-sensitive cultivated wheat genotypes, as well as in the wild wheat genotypes, Triticum and Aegilops using qRT-PCR. The MtATP6 expression was suddenly induced 3 h after NaCl treatment in all genotypes, indicating an early inducible stress-responsive behavior. Promoter analysis showed that the MtATP6 promoter includes cis-acting elements such as ABRE, MYC, MYB, GTLs, and W-boxes, suggesting a role for this gene in abscisic acid-mediated signaling, energy metabolism, and stress response. It seems that 6-kDa subunit, as an early response gene and nuclear regulatory factor, translocates to mitochondria and completes the F₁F₀-ATP synthase complex to enhance ATP production and maintain ion homeostasis under stress conditions. These communications between nucleus and mitochondria are required for inducing mitochondrial responses to stress pathways. Dual targeting of 6-kDa subunit may comprise as a mean of inter-organelle communication and save energy for the cell. Interestingly, MtATP6 showed higher and longer expression in the salt-tolerant wheat and the wild genotypes compared to the salt-sensitive genotype. Apparently, salt-sensitive genotypes have lower ATP production efficiency and weaker energy management than wild genotypes; a stress tolerance mechanism that has not been transferred to cultivated genotypes.     

Structure-activity study of phosphoramido acid esters as acetylcholinesterasf inhibitors

Phosphoramido acid esters (CH₃)₂NP(O)X(p-OC₆H₄-CH₃) (containing P-Cl (1), P-O (2), P-F (3), P-CN (5), and P-N (4,6) bonds, X for 2, 4 and 6 is OCH₃, (C₂H₅)₂N and morpholin) have been synthesized to investigate the structure-activity study of AChE enzyme inhibition, through the parameters logP, δ³¹P and IC₅₀. After their characterization by ³¹P, ³¹P{¹H}, ¹³C, ¹H NMR, IR and mass spectroscopy, the parameters logP and δ³¹P (³¹P chemical shift in NMR) were used to evaluated the lipophilicity and electronical properties. The ability of compounds to inhibit human AChE was predicted by PASS software (version 1.193), and experimentally evaluated by a modified Ellman's assay.