Organophosphorus compounds (OP) are chemicals widely used as pesticides in different applications such as agriculture and public health (vector control), and some of the highly toxic forms have been used as chemical weapons. After application of OPs in an environment, they persist for a period, suffering a degradation process where the biotic factors are considered the most relevant forms. However, to date, the biodegradation of OP compounds is not well understood. There are a plenty of structure-based biodegradation estimation methods, but none of them consider enzymatic interaction in predicting and better comprehending the differences in the fate of OPs in the environment. It is well known that enzymatic processes are the most relevant processes in biodegradation, and that hydrolysis is the main pathway in the natural elimination of OPs in soil samples. Due to this, we carried out theoretical studies in order to investigate the interactions of these OPs with a chosen enzyme—the phosphotriesterase. This one is characteristic of some soils’ microorganisms, and has been identified as a key player in many biodegradation processes, thanks to its capability for fast hydrolyzing of different OPs. In parallel, we conducted an experiment using native soil in two conditions, sterilized and not sterilized, spiked with specific amounts of two OPs with similar structure—paraoxon-ethyl (PXN) and O-(4-nitrophenyl) O-ethyl methylphosphonate (NEMP). The amount of OP present in the samples and the appearance of characteristic hydrolysis products were periodically monitored for 40 days using analytical techniques. Moreover, the number of microorganisms present was obtained with plate cell count. Our theoretical results were similar to what was achieved in experimental analysis. Parameters calculated by enzymatic hydrolysis were better for PXN than for NEMP. In soil, PXN suffered a faster hydrolysis than NEMP, and the cell count for PXN was higher than for NEMP, highlighting the higher microbiological toxicity of the latter. All these results pointed out that theoretical study can offer a better comprehension of the possible mechanisms involved in real biodegradation processes, showing potential in exploring how biodegradation of OPs relates with enzymatic interactions.

B. anthracis was used in bioweapon programs of many countries, such as Germany during World War I, Japan in World War II, the former Union of Soviet Socialist Republics (USSR) (1928-1992), United States of America (USA) (1941-1969), Iraq (1970-1991) and others. In addition, it was used in bioterrorist attacks perpetrated by Aum Shinrikyo (1995, Japan, no fatalities) and the Amerithrax (2001, USA, five people killed and 22 infected). It is classified by the Centers for Disease Control and Prevention (CDC) as a Tier 1 biological agent.^3,4

Bacillus anthracis is a Gram-positive, spore-forming bacterium and the etiological agent of anthrax, a re-emerging, septicemic, hemorrhagic, and often lethal disease that affects humans as well as domestic and wild ruminants. Owing to its high lethality, spore stability, and ease of dissemination, this pathogen is recognized as a major biological-warfare agent and is classified among the Category A bioterrorism threats. Rapid and unequivocal identification is essential; however, it is hindered by the extensive similarity between B. anthracis and closely related species, particularly Bacillus cereus. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as an increasingly adopted tool in diagnostic laboratories due to its cost-effectiveness, speed, and reliability in microorganism identification (Infographic 1). This comprehensive review compiles known B. anthracis biomarkers and evaluates the methodologies employed across scientific studies via systematic bibliographic analysis. We identified 87 B. anthracis biomarkers reported in the literature and classified them according to their specificity relative to those of other members of the B. cereus group. Moreover, we highlight gaps in methodological standardization and biomarker validation, emphasizing the need to develop robust protocols capable of ensuring the accurate detection of B. anthracis in biological defense contexts and surveillance. Accordingly, we propose a standardized analytical workflow aimed at improving diagnostic reliability, with recommended tools and best practices for enhancing the application of mass spectrometry in the specific identification of B. anthracis.