Biometals最新文献

Mercury is widely known for its detrimental effects on living organisms, whether in its elemental or bonded states. Recent comparative studies have shed light on the biochemical implications of mercury ingestion, both in low, persistent concentrations and in elevated acute dosages. Studies have presented models that elucidate how mercury disrupts healthy cells. Mercury's unique ability to interfere with crucial enzymatic processes at deposition sites is a vital feature of these models. The strong affinity for the sulfhydryl moieties of enzyme catalytic sites leads to enzyme inactivation through permanent covalent modifications. This inactivation can have catastrophic effects on an organism's metabolic functions. Moreover, it has been found that mercury's binding to sulfhydryl moieties is highly nonspecific and can occur in various ways. This review aimed to explore the effects of mercury on a broad spectrum of enzymes with a specific focus on how these alterations can detrimentally affect several metabolic pathways.

The objective of the present study was to assess serum and cancerous tissue biometal levels in colorectal cancer (CRC) patients, and its relation to disease severity. A total of 90 CRC patients and 97 controls were involved in the present study. The level of biometals in blood serum and colon tissues (only in CRC cases) was evaluated by inductively-coupled plasma mass-spectrometry. CRC patients are characterized by lower serum Ca, Fe, Se, and Zn, as well as higher serum Co, Cu, Mg, V, and Cu/Zn ratio compared to healthy controls. The lowest serum Zn levels and the highest Cu concentration and Cu/Zn ratio were observed in patients with the largest tumor size. Regression analysis demonstrated that tumor size is a significant negative predictor of serum Se levels, being positively associated with serum Cu/Zn values. The degree of metastasis to regional lymph nodes was inversely associated with circulating Ca, Co, Mg, Zn, and Mn levels. Serum Mg and Mn levels were positively associated with the stage of the disease and tumor location, respectively. Cancerous tissue Ca and Mo levels were lower, while Mg content was higher compared to healthy adjacent tissues. In cancerous tissues a constant but non-significant trend to elevation of tissue Zn content with increasing tumor size was observed. In addition, serum Cu, Zn, and Cu/Zn values positively correlated with the respective tumor values. These findings demonstrate that altered biometal metabolism is associated with CRC, while systemic Cu/Zn ratio may be indicative of Cu and Zn imbalance in cancerous tissue.

Zinc is an essential metal to living organisms, including corals and their symbiotic microalgae (Symbiodiniaceae). Both Zn(II) deprivation and overload are capable of leading to dysfunctional metabolism, coral bleaching, and even organism death. The present work investigated the effects of chemically defined Zn species (free Zn, ZnO nanoparticles, and the complexes Zn-histidinate and Zn-EDTA) over the growth of the dinoflagellates Symbiodinium microadriaticum, Breviolum minutum, and Effrenium voratum, and on the trypsin-like proteolytic activity of the hydrocoral Millepora alcicornis. B. minutum was the most sensitive strain to any form of added Zn. For the other strains, the complex [Zn(His)₂] better translated metal load into growth. This complex was the only tested compound that did not interfere with the trypsin-like activity of Millepora alcicornis extracts. Also, histidine was able to recover the activity of the enzyme inhibited by zinc. [Zn(His)₂] is a potential biocarrier of zinc for microalgae or coral cultivation. These findings suggest that the control of chemical speciation of an essential metal could lead to useful compounds that assist autotrophy, while not affecting heterotrophy, in the coral holobiont.

A novel biosynthesis approach was used to develop zinc selenite (ZnSeO₃) catalysts from the plant extracts of Nephrolepis cordifolia (ZnSeO₃:NC) and Ziziphus jujube (ZnSeO₃:ZJ) using hydrothermal method. This study investigates the structural, morphological, and optical properties of pure and biosynthesized ZnSeO₃ catalysts. X-ray diffraction (XRD) analysis confirms the presence of an orthorhombic phase in both catalyst types. Fourier transform infrared spectroscopy (FTIR) reveals the incorporation of secondary metabolites in the biosynthesized ZnSeO₃ catalysts, indicating successful green synthesis. Field-emission scanning electron microscopy (FESEM) demonstrates the formation of needle-shaped nanorod morphology in the prepared catalysts. UV-visible spectroscopy shows a red shift in the optical band gap, with values ranging from 2.40 to 1.60 eV for the biosynthesized ZnSeO₃ catalysts, suggesting enhanced light absorption properties. Barrett-Joyner-Halenda (BJH) analysis highlights the significant influence of plant extract on the surface area of the biosynthesized catalysts. The synthesized ZnSeO₃ catalysts were analyzed for the degradation of Oxytetracycline (OTC) and Rhodamine B (RhB) dyes as well as for their antibacterial activity. Notably, ZnSeO₃:ZJ catalysts demonstrated enhanced OTC degradation (99%) within 100 min. and RhB dye degradation (99%) within 120 min. The improved kinetic energy, effect of pH, catalysis dosage concentration and scavenger performance for ZnSeO₃:ZJ catalysts against OTC and RhB dyes compared to pure and ZnSeO₃:NC photocatalysts. ZnSeO₃:ZJ exhibits improved growth of inhibition zone against bacterial pathogen B. subtilis (3.30 ± 0.00) followed by E. coli (2.73 ± 0.06). This enhanced degradation efficiency is attributed to the presence of secondary metabolites in the Ziziphus jujube plant extract. These results suggest these catalysts could effectively eliminate wastewater contaminants and innovative antibacterial medications, benefiting the pharmaceutical sector.

Increasing antibiotic resistance among the common nosocomial pathogen i.e. Acinetobacter baumannii poses life threat to the health care workers as well as to the society. The dissemination of antibiotic resistance in this pathogen at an alarming rate could be not only due to the overuse of antibiotics but also due to the stress caused by exposure of bacterium to several environmental contaminants in their niches. In the present study, effect of copper stress on augmentation in the antibiotic resistance of A. baumannii MCC 3114 against three clinically used antibiotics was investigated along with the phenotypic and genotypic alterations in the cell. It induced 8, 44 and 22-fold increase in resistance against colistin, ciprofloxacin and levofloxacin, respectively. Moreover, the biofilm formation of adapted culture was significantly enhanced due to a dense EPS around the cell (as revealed by SEM images). The structural changes in EPS were demonstrated by FTIR spectroscopy. The adequate growth of adapted MCC 3114 despite increased level of ROS indicates its persistence in copper and ROS stress. The physiological alterations in cell viz., increased efflux pump activity and decreased membrane permeability was observed. Molecular analysis revealed increased expression of efflux pump related genes, oxidative stress genes, integron and antibiotic resistance genes. In sum, our study revealed that the exposure of the critical pathogen, A. baunmannii to copper in hospital settings and environmental reservoirs can impose adaptive pressure which may lead to genotypic as well phenotypic changes in cell resulting into the augmentation of antibiotic resistance.