Antibacterial drugs are among the most commonly used medications in the world. Tetracycline is a widely used antibiotic for human and animal therapy due to its broad-spectrum activity, high effectiveness, and reasonable cost. The indications for treatment with tetracycline include pneumonia, bone and joint infections, infectious disorders of the skin, sexually transmitted and gastrointestinal infections. However, tetracycline has become a serious threat to the environment because of its overuse by humans and veterinarians and weak ability to degrade. Tetracycline is capable of accumulating along the food chain, causing toxicity to the microbial community, encouraging the development and spread of antibiotic resistance, creating threats to drinking and irrigation water, and disrupting microbial flora in the human intestine. It is essential to address the negative impact of tetracycline on the environment, as it causes ecological imbalance. Ineffective wastewater systems are among the main reasons for the increased antibiotic concentrations in aquatic sources. It is possible to degrade tetracycline by breaking it down into small molecules with less harmful or nonhazardous effects. A range of methods for physical, chemical, and biological degradation exists. The review will discuss the negative effects of tetracycline consumption on the aquatic environment and describe available removal methods.

The prevalence of Type 2 Diabetes Mellitus (T2DM) is internationally ever-growing. Therefore, prevention, diagnostics, and control of insulin resistance and T2DM are of increasing importance. It has been suggested that mechanisms leading to insulin resistance and diabetes and its complications include high intake of refined and energy-rich food, which is presumed to be accompanied by suboptimal intake of trace elements, such as Zinc (Zn), Selenium (Se), Chromium (Cr), and Copper (Cu), which are essential and crucial for various biological processes. The purpose of this review is to highlight the role of Zn, Se, and Cu in T2DM. Diabetes seems prevalent when Zn, Se, and Cu are deficient, which may result from excessive intake of refined food. The literature search was conducted in PubMed and Scopus, supplemented with the reference lists of relevant articles and a Google Scholar search. We critically assessed all relevant citations, both review and research papers in English. The search terms that were used included Zn, Cu, diabetes, and diabetes mellitus. Research has shown that Zn, Se and Cu are involved in the pathogenesis of diabetes, but these trace elements can in excessive amounts be toxic. Zinc appears to activate key molecules that are involved in cell signaling, which maintain the homeostasis of glucose. Zinc also regulates insulin receptors, prolong the action of insulin, and promote healthy lipid profiles. Copper in excess can create oxidative stress, which is a factor in the onset and the progression of T2DM. Abnormal Zn and Cu metabolism appears to accompany and may also cause diabetes complications.

The immune system protects the body from infectious agents such as bacteria, viruses, or fungi. Once encountered with pathogens or antigens, the innate and adaptive arms of the immune system trigger a strong immune response to eliminate them from the system and protect the body. Thus, well-balanced immunity is pivotal for maintaining human health, as an insufficient level of immune defense leads to infections and tumors. In contrast, the excessive functioning of the immune system causes the development of autoimmune diseases and allergies. Strong immunity requires adequate nutrition, dietary interventions, and sufficient intake of certain vitamins (vitamin C, vitamin D, and folic acid) and minerals (magnesium, zinc, and selenium). Therefore, nutritional and micronutrient deficiencies lead to compromised immunity. Several natural ingredients have shown potent immunomodulatory properties. The immune-enhancing properties of many plants and fungi are due to containing bioactive phytoconstituents such as polyphenols, terpenoids, β-glucans, vitamins, etc. Probiotics and prebiotics can be used as innovative tools to reduce intestinal inflammation and downregulate hypersensitivity reactions. Plant sources of melatonin, a multifunctional molecule with proven anti-inflammatory and immunomodulatory properties, have been discovered relatively recently. The bioactive compounds augment the immune response by directly increasing the cytotoxic activity of natural killer cells, macrophages, and neutrophils. Many phytoconstituents prevent cell damage due to their powerful antimicrobial, antioxidant, and anti-inflammatory properties. The present review attempts to understand the molecular mechanisms underlying the immune-enhancing properties of some bioactive compounds from plants, fungi, animals, microorganisms, and other natural sources.

Iron deficiency (ID) is particularly frequent in obese patients due to increased circulating levels of acute-phase reactant hepcidin and adiposity-associated inflammation. Inflammation in obese subjects is closely related to ID. It induces reduced iron absorption correlated to the inhibition of duodenal ferroportin expression, parallel to the increased concentrations of hepcidin. Obese subjects often get decreased inflammatory response after bariatric surgery, accompanied by decreased serum hepcidin and therefore improved iron absorption. Bariatric surgery can induce the mitigation or resolution of obesity-associated complications, such as hypertension, insulin resistance, diabetes mellitus, and hyperlipidemia, adjusting many parameters in the metabolism. However, gastric bypass surgery and sleeve gastrectomy can induce malabsorption and may accentuate ID. The present review explores the burden and characteristics of ID and anemia in obese patients after bariatric surgery, accounting for gastric bypass technique (Roux-en-Y gastric bypass—RYGB) and sleeve gastrectomy (SG). After bariatric surgery, obese subjects’ iron status should be monitored, and they should be motivated to use adequate and recommended iron supplementation.