Interactions between metals and microbes are critical in geomicrobiology and vital in microbial ecophysiological processes. Methane-oxidizing bacteria (MOB) and ammonia-oxidizing microorganisms (AOM) are key members in aerobic environments to start the C and N cycles. Ammonia and methane are firstly oxidized by copper-binding metalloproteins, monooxygenases, and diverse iron and copper-containing enzymes that contribute to electron transportation in the energy gain pathway, which is evolutionally connected between MOB and AOM. In this review, we summarized recently updated insight into the diverse physiological pathway of aerobic ammonia and methane oxidation of different MOB and AOM groups and compared the metabolic diversity mediated by different metalloenzymes. The elevation of iron and copper concentrations in ecosystems would be critical in the activity and growth of MOB and AOM, the outcome of which can eventually influence the global C and N cycles. Therefore, we also described the impact of various concentrations of metal compounds on the physiology of MOB and AOM. This review study could give a fundamental strategy to control MOB and AOM in diverse ecosystems because they are significantly related to climate change, eutrophication, and the remediation of contaminated sites for detoxifying pollutants.

Background: Type II Diabetes Mellitus (Type II DM) is a complex systemic disorder that affects various organs and has been strongly associated with an increased risk of cognitive impairments, including dementia. The Ciliary Neurotrophic Factor (CNTF) gene is implicated in the pathophysiology of diabetes-induced cognitive decline, suggesting its potential as a biomarker for neurodegenerative diseases. Objective: The primary objective of this study was to investigate the expression of the CNTF gene in diabetic patients with dementia and to evaluate its correlation with cognitive dysfunction. Methods: A cohort of 88 diabetic dementia patients and 12 healthy controls was selected based on inclusion criteria. CNTF serum levels were measured using Chemiluminescent immunoassay (CLIA), and CNTF gene expression was assessed through real-time PCR. DNA was isolated using the QIAgen blood kit, followed by bisulfite DNA modification and Methylation Specific PCR for methylation profiling. Data analysis included comparative studies using GraphPad Prism 9.0 with statistical significance set at a p-value of <0.05. Results: The study found that CNTF serum levels in diabetic dementia patients (n=88) were significantly lower at 4.98 µg/mL compared to 14.21 µg/mL in healthy controls (n=12). MMSE scores were also reduced in the patient cohort, averaging 10.98 versus 25.6 in controls. A notable decrease in CNTF gene expression was observed with a fold change of approximately 4.1 in diabetic dementia patients, indicating underexpression in this group. Conclusion: CNTF gene expression is inversely correlated with cognitive function in diabetic patients, suggesting that CNTF could serve as a useful biomarker for the early detection of dementia in this population. The identification of this gene's role opens new avenues for targeted therapeutic interventions and enhances the understanding of dementia's etiology in diabetic patients.