Effect of Cd2+ on muscle type of creatine kinase: Inhibition kinetics integrating computational simulations

Enrichment and immobilization of heavy metal ions from wastewater by nanocellulose/carbon dots-derived composite

Heavy metal ions (HMIs) have been widely applied in various industries because of their excellent physicochemical properties. However, their discharging without appropriate treatment brought about serious pollution problems. So it is desirable but challenging to rapidly and completely clean up these toxic pollutants from water, especially utilizing environmentally friendly and naturally rich biomass materials. In this work, we prepared nanocellulose/carbon dots/magnesium hydroxide (CCMg) ternary composite using cotton via a simple hydrothermal method. The removal mechanism towards Cd2+ and Cu2+ was investigated using a combination of experimental techniques and density functional theory calculations. CCMg shows a good ability to remove HMIs. It is realized that the interaction between each component of CCMg and cadmium nitrate is mainly of hydrogen/dative bonds. Cadmium nitrate is preferentially enriched by the Mg(OH)2 moiety, proved by calculated thermodynamics, interfacial interactions and charges. After transformation, the cadmium carbonate precipitate is fixed on the surface by nanocellulose (NC) via chemical coupling; and of interest is that copper ion precipitates in the form of basic sulfate. Due to its high adsorption effect and simple recovery operation, CCMg is having a wide range of application prospects as a water treatment agent.

Kinetic analysis of the transphosphorylation with creatine kinase by pressure-assisted capillary electrophoresis/dynamic frontal analysis

Kinetic reactions of the transphosphorylation with creatine kinase (CK) were individually investigated between creatine (Cr) and creatine phosphate (CrP) by pressure-assisted capillary electrophoresis/dynamic frontal analysis (pCE/DFA). The transphosphorylations are reversible between Cr and CrP, and reverse reactions inevitably accompany in general batch analyses. In pCE/DFA, the kinetic reaction proceeds in a separation capillary and the product is continuously resolved from the substrate zone. Therefore, the formation rate is kept constant at the substrate zone without the reverse reaction, and the product is detected as a plateau signal. This study demonstrates the direct and individual analyses of both the forward and the backward kinetic reactions with CK by pCE/DFA. A plateau signal was detected in the pCE/DFA with ADP or ATP as one of the products on either the forward or the backward reactions. The Michaelis-Menten constants of K_m,ATP (from Cr to CrP) and K_m,ADP (from CrP to Cr) were successfully determined through the plateau signal. Determined values of K_m,ATP and K_m,ADP by pCE/DFA were smaller than the ones obtained by the pre-capillary batch analyses. The results agree with the fact that the reverse reaction is excluded in the analysis of the kinetic reactions. The proposed pCE/DFA is useful on individual analyses of both forward and backward kinetic reactions without any interference from the reverse reaction.

Comparative studies of the expression of creatine kinase isoforms under immune stress in Pelodiscus sinensis

The expression and localization of different isoforms of creatine kinase in Pelodiscus sinensis (PSCK) were studied to reveal the role of PSCK isozymes (PSCK-B, PSCK-M, PSCK-S) under bacterial infection-induced immunologic stress. The computational molecular dynamics simulations predicted that PSCK-S would mostly possess a kinase function in a structural aspect when compared to PSCK-B and PSCK-M. The assay of biochemical parameters such as total superoxide dismutase (T-SOD), lactate dehydrogenase (LDH), malondialdehyde (MDA), catalase (CAT), and the content of ATP were measured along with total PSCK activity in different tissue samples under bacterial infection. The expression detections of PSCK isozymes in vitro and in vivo were overall well-matched where PSCK isozymes were expressed differently in P. sinensis tissues. The results showed that PSCK-B mostly contributes to the spleen, followed by the liver and myocardium; PSCK-M mostly contributes to the liver, followed by the myocardium and skeletal muscle, while PSCK-S contributes to the spleen and is uniquely expressed in skeletal muscle. Our study suggests that the various alterations of PSCK isozymes in tissues of P. sinensis are prone to defense the bacterial infection and blocking energetic imbalance before severe pathogenesis turned on in P. sinensis.

Effects of sub-chronic, low-dose cadmium exposure on kidney damage and potential mechanisms

Background

The present study was to investigate the potential mechanisms underlying the sub-chronic low-dose cadmium (Cd) exposure induced renal injury in rats.

Methods

Totally 40 male adult SD rats were randomly divided into four groups: control group, low-dose Cd group (1 mg/kg CdCl₂), moderate-dose Cd group (2.5 mg/kg) and high-dose Cd group (5 mg/kg).

Results

From the 3^rd week, the body weight of rats in moderate-dose and high-dose declined significantly as compared to the control group (P<0.05); the liver to body weight ratio increased, the volumes of 24-hour urine and drinking-water decreased markedly (P<0.05), the BUN, SCr and β₂-MG increased significantly, but the Fe²⁺ concentration decreased markedly as compared to the control group (P<0.05); the serum MDA and SOD₁ content contents increased, but the serum SOD₂ and CAT contents decreased significantly in Cd-treated groups (P<0.05); Renal injury deteriorated with the increase in Cd dose; swelling glomeruli showed stenotic renal-tubules, and epithelial-cell-necrosis, shedding and accumulation in the lumen, massive infiltrated inflammatory cells and interstitial hyperaemia were observed; The mitochondria in renal-tubular-epithelial-cells displayed swelling, deformation and vacuolation; the renal ROS content increased in Cd-exposure-groups; the renal SOD₁ expression increased but the expression of SOD₂ and CAT decreased (P<0.05). The Bcl-2 expression decreased, but Bax expression and Bax/Bcl-2 ratio increased significantly in a Cd-dose dependent manner.

Conclusions

Cd may cause renal injury in a dose dependent manner, which may be ascribed to the disordered Fe²⁺ absorption, redox imbalance and apoptosis in the kidney.

Characterization of the binding mechanism and conformational changes of bovine serum albumin upon interaction with aluminum-maltol: a spectroscopic and molecular docking study

The widespread use of aluminum in the treatment of drinking water, food, agriculture and pharmaceuticals has greatly increased the risk of human exposure to excess aluminum, which is a serious health hazard to human beings.