Synthesis of cyclopentadienyl ruthenium complexes containing 5-membered N-heterocyclic thiolates

Mononuclear ruthenium-thiolate complexes of structural type CpRu(PPh₃)₂SR (1) [R = 2-imidazolyl (a), 1-methylimidazolyl (b), 5-methyl-1,3,5-thiadiazolyl (c) and 5-methyl-4H-1,2,4-triazolyl (d)] are accessible from the reaction of CpRu(PPh₃)₂Cl with the corresponding thiolate anions. Reaction of CpRu(PPh₃)₂Cl with the heterocyclic-thiolate anions in the presence of the bisphosphine ligands affords CpRu(P-P)SR [P-P = bis(diphenylphosphino)methane; dppm (2), bis(diphenylphosphino)ethane; dppe (3)]. If CO gas was bubbled through a THF solution of 1b, the complex CpRu(PPh₃)(CO)S(C₄N₂H₅) (4b) is produced. These ruthenium-heterocyclic thiolate complexes have been characterized by elemental analysis, spectroscopy (IR, ¹H, ³¹P{¹H} NMR and MS) and cyclic voltammetry for some samples. The solid-state structures of 3a and 3b are determined by single-crystal X-ray structure analysis.     

The economic dimension of directing treated wastewater to the production of green fodder in Saudi Arabia

This study aimed to identify the economic dimension of directing treated wastewater to the production of green fodder. To achieve its objectives, the study relied on economic equations, the method of using multiple criteria, and a scoring technique for prioritization. The study showed that green fodder is a crop that depletes water, as it consumes about 67.27% of the water used for agricultural purposes. In determining the priority of regions intending to use treated wastewater, the ranking put Riyadh region first, followed by the eastern region, the Qassim region, Hail, Makkah Al-Mukarramah, Tabuk, Asir, Al-Jawf, Jizan, Madinah, Najran, the northern borders, and Al-Baha, in this order. The area that can be cultivated with forage crops is estimated to be about 53.05 thousand hectares, with a production of 953.75 thousand tons. The cost of treating wastewater to make it usable amounts to 2126.22 million riyals, while the value of the benefits gained from its use is 2508.95 million riyals; thus, the Saudi agricultural economy achieves a net gain estimated at about 382.73 million riyals annually. Therefore, this study recommends the use of treated wastewater in the production of green fodder.     

Role of NF-κB/IL-1β Pathway and Caspase 3 in Mediating the Hepatoprotective Effect of Rutin against Paraquat-Induced Liver Toxicity in Male Rats

One of the most common bipyridinium herbicides that can lead to liver toxicity is paraquat. Rutin is a bioflavonoid with antioxidant, anti-inflammatory, anti-hepatotoxic, and antimicrobial properties. The effect of rutin on paraquat-induced liver toxicity was examined in this study. 48 male rats were divided into six groups: the control group was given a normal diet; the non-treated group was given paraquat; the positive control group was given paraquat, and silymarin and the treatment groups were given paraquat and rutin at doses of 25, 50, and 100 mg/kg. After fourteen days, the rats were anesthetized by xylazine-ketamine, and fasting blood samples were obtained from their hearts to measure alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT), malondialdehyde (MDA), creatinine, lipid profile, antioxidant capacity, and carbonyl protein. The liver tissue was removed to measure the levels of catalase (CAT), superoxide dismutase (SOD), total protein, vitamin C, plus NF-κB, IL1β, and caspase-3 gene expressions. Paraquat gavage in the untreated group (group 2) for 14 days in comparison with the control group induced a significant augmentation (p<0.05) in levels of lipid profile, AST, ALP, ALT, MDA, carbonyl protein, and also NF-κB, IL1β, Caspase3 expressions. Treatment with rutin reduced the factors as mentioned above. Paraquat poisoning induced a substantial decline (p<0.05) in HDL content, FRAP level, CAT, and SOD activity of the liver compared to the control group. However, rutin oral treatment led to a substantial increase (p<0.05) in the level of these factors compared to the paraquat-only treated group. Based on the findings of the present study, it was found that rutin can be significantly effective in improving hepatotoxicity caused by paraquat.     

Effect of sex hormones on human T cell activation by concanavalin A

The effect of sex hormones on concanavalin A (Con A)-activated human T cells was studied. We show that neither 17 beta-estradiol (E2) nor progesterone, in concentrations of up to 10(-6) M, alters the proliferative response of peripheral-blood mononuclear cells (PBMC) of healthy postmenopausal women. Furthermore, the hormones had no effect on the composition of T cell populations and on the expression of activation markers. We extended our study to a unique T cell population that is characterized by the ability to form rosettes with human erythrocytes, following Con A activation (designated autorosette-forming cells; ARFC) and known to manifest suppressive activity. Indeed, the in vitro addition of E2 (neither progesterone nor testosterone) to Con A-stimulated PBMC brought an about 2- to 4-fold increase in the frequency of ARFC. Tamoxifen, an antiestrogen drug, reduced the frequency of estrogen-stimulated ARFC to the original low level. Furthermore, the inhibitory effect of growth medium from ARFC cultures originally stimulated with Con A + E2 was found to be higher than that of ARFC cultures originally stimulated with Con A alone.     

Thermoalkalophilic lipase from an extremely halophilic bacterial strain Bacillus atrophaeus FSHM2: Purification,biochemical characterization and application

The present study was designed to isolate and identify an extremely halophilic lipase-producing bacterial strain, purify and characterize the related enzyme and evaluate its application for ethyl and methyl valerate synthesis. Among four halophilic isolates, the lipolytic ability of one isolate (identified as Bacillus atrophaeus FSHM2) was confirmed. The enzyme (designated as BaL) was purified using three sequential steps of ethanol precipitation and dialysis, Q-Sepharose XL anion-exchange chromatography and SP Sepharose cation-exchange chromatography with a final yield of 9.9% and a purification factor of 31.8. The purified BaL (Mw～85?kDa) was most active at 70?°C and pH 9 in the presence of 4 M NaCl and retained 58.7% of its initial activity after 150?min of incubation at 80?°C. The enzyme was inhibited by Cd²⁺ (35.6?±?1.7%) but activated by Ca²⁺ (132.4?±?2.2%). Evaluation of BaL's stability in the presence of organic solvents showed that xylene (25%) enhanced the relative activity of the enzyme to 334.2?±?0.6% after 1?h of incubation. The results of esterification studies using the purified BaL revealed that maximum ethyl valerate (88.5%) and methyl valerate (67.5%) synthesis occurred in the organic solvent medium (xylene) after 48?h of incubation at 50?°C.     

N,N-Dichloroaminosulfonic acids as novel topical antimicrobial agents

2-Dichloroamino-2-methyl-propane-1-sulfonic acid sodium salt (2a), a stable derivative of endogenous N,N-dichlorotaurine (1), has been identified and is under development as a topical antimicrobial agent. Structure–activity relationships of analogs were explored to achieve optimal antimicrobial activity with minimal mammalian toxicity while maintaining the desired stability. All the analogs synthesized showed antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans in the range of 1–128 μg/mL and cytotoxicity against mammalian L929 cells in the range 80–1900 μg/mL.     

Pyridine-Functionalized Fe3O4 Nanoparticles as a Novel Sorbent for the Preconcentration of Lead and Cadmium Ions in Tree Leaf as a Bioindicator of Urban Traffic Pollution

We have developed a facile and highly sensitive sorbent for cadmium and lead ions. It is based on Fe₃O₄ nanoparticles functionalized with a derivative of picoline and was characterized by scanning electron microscopy, differential thermographic analysis, and elemental analysis. The material can be applied to the preconcentration of lead and cadmium ions. Factors such as the type, concentration and volume of eluent, the pH of the sample solution, the time for extraction, and the volume of the sample were studied. The effects of a variety of ions on preconcentration and recovery of these ions were also investigated. The ions were determined by FAAS, and the limits of detection are <0.8 and <0.061???g?L^?1 for lead and cadmium, respectively. Recoveries and precisions are >98.0?% and <1.3?%, respectively. The method was validated by analyzing several certified leaf reference materials.     

Enzyme diffusion and action on soluble and insoluble substrate biopolymers

The action of enzymes on soluble and insoluble substrate biopolymers is discussed, taking into account enzyme diffusion along the biopolymer “surface” and interaction with interspersed ligand groups that may be modified by the action of the enzyme. It is shown that movement of the enzyme under trhe combined effect of these two processes can be described as a diffusion process characterized by an apparent diffusion coefficient that generally depends on both time and position. Equations describing the system are formulated and some specific examples analyzed in terms of analytical or numerical solutions. The concentration distributions of both the enzyme and the substrate (or product ) were obtained for different systems for which the apparent diffusion coefficient is a function of time only, as well as of both time and position. The relevance of the formulation, as developed, to systems in which reduction in dimensionality leads to enhanced enzyme efficiency is discussed, and possible uses of the theory in studies of biopolymer structure and enzyme-biopolymer interactions are suggested.