https://aquaticpath.phhp.ufl.edu/waterbiology/handouts/Microcystins2004.pdf

Microcystin-producing blooms--a serious global public health issue.

Fluoride is widely used as an anticaries agent in drinking water and a variety of other vehicles. This use has resulted in major health benefits. However, there are still open questions regarding the mechanisms of anticaries action and the importance of antimicrobial effects in caries reduction. Fluoride acts in multiple ways to affect the metabolism of cariogenic and other bacteria in the mouth. F−/HF can bind directly to many enzymes, for example, heme-containing enzymes or other metalloenzymes, to modulate metabolism. Fluoride is able also to form complexes with metals such as aluminum or beryllium, and the complexes, notably AlF4− and BeF3−·H2O, can mimic phosphate with either positive or negative effects on a variety of enzymes and regulatory phosphatases. The fluoride action that appears to be most important for glycolytic inhibition at low pH in dental plaque bacteria derives from its weak-acid properties (pKa=3.15) and the capacity of HF to act as a transmembrane proton conductor. Since many of the actions of fluoride are related to its weak-acid character, it is reasonable to compare fluoride action to those of organic weak acids, including metabolic acids, food preservatives, non-steroidal anti-inflammatory agents and fatty acids, all of which act to de-energize the cell membrane by discharging ΔpH. Moreover, with the realization that the biofilm state is the common lifestyle for most microorganisms in nature, there is need to consider interactions of fluoride and organic weak acids with biofilm communities. Hopefully, this review will stimulate interest in the antimicrobial effects of fluoride or other weak acids and lead to more effective use of the agents for disease control and other applications.

http://dzumenvis.nic.in/microbes and metals interaction/pdf/fluoride and organic weak acids.pdf

Fluoride and organic weak acids as modulators of microbial physiology.

SUMMARY Cadmium (Cd) is a heavy metal found as an environmental contaminant, both through natural occurrence and from industrial and agricultural sources. Foodstuffs are the main source of cadmium exposure for the non-smoking general population. Cadmium absorption after dietary exposure in humans is relatively low (3–5 %) but cadmium is efficiently retained in the kidney and liver in the human body, with a very long biological half-life ranging from 10 to 30 years. Cadmium is primarily toxic to the kidney, especially to the proximal tubular cells where it accumulates over time and may cause renal dysfunction. Cadmium can also cause bone demineralisation, either through direct bone damage or indirectly as a result of renal dysfunction. After prolonged and/or high exposure the tubular damage may progress to decreased glomerular filtration rate, and eventually to renal failure. The International Agency for Research on Cancer has classified cadmium as a human carcinogen (Group 1) on the basis of occupational studies. Newer data on human exposure to cadmium in the general population have been statistically associated with increased risk of cancer such as in the lung, endometrium, bladder, and breast. Cadmium bioavailability, retention and consequently toxicity are affected by several factors such as nutritional status (low body iron stores) and multiple pregnancies, preexisting health conditions or diseases. A health based guidance value for cadmium of 7 μg/kg body weight (b.w.) per week (Provisional Tolerable Weekly Intake (PTWI)) was established previously by the Joint 1 For citation purposes: Scientific Opinion of the Panel on Contaminants in the Food Chain on a request from the European

/pdf/scientific-opinion-of-the-panel-on-contaminants-in-the-food-4g58bdunry.pdf

Scientific Opinion of the Panel on Contaminants in the Food Chain

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793%2803%2901447-9

Microcystin-LR and okadaic acid-induced cellular effects: a dualistic response

Cyanotoxins produced by cyanobacteria (blue-green algae) include potent neurotoxins and hepatotoxins. The hepatotoxins include cyclic peptide microcystins and nodularins plus the alkaloid cylindrospermopsins. Among the cyanotoxins the microcystins have proven to be the most widespread, and are most often implicated in animal and human poisonings. This paper presents a practical guide to two widely used methods for detecting and quantifying microcystins and nodularins in environmental samples-the enzyme linked immunosorbant assay (ELISA) and the protein phosphatase inhibition assay (PPIA).

Margrethe Hauge Serres

Papers

Sensitive detection of apoptogenic toxins in suspension cultures of rat and salmon hepatocytes

An ultrasensitive competitive binding assay for the detection of toxins affecting protein phosphatases.