What is the reason for the stench of the stool? How foul-smelling molecular activity is inhibited.

Recently, a U.S.-China team has felt the sweet smell of success: they have found an iconic enzyme that can be used to identify the bacteria's foul-smelling molecule, 3-methylpyrifos- fecal skunk.
the results of the study may help develop ways to inhibit the activity of this foul-smelling molecule.
"Simply put, our findings explain why animal waste smells. Zhang Wei, a biochemist at Tianjin University and co-author of the
research, told China Science Daily.
Although it has long been known that fecal skunk is fermented by the bacteria tryptophan, until then, the enzymes that catalyzed it were not known. using comparative genomics, the researchers
found that pyrethronic acid depyrizose as a genetic marker could be used to identify environmental bacteria that produce fecal skunk and those associated with humans.
this result adds to the growing chemical pool of the glycotamine free radical seise superfamily, which will further have an impact on human health and animal husbandry.
ane-drug catalyzing" fecal skunk is a stinking compound that is a unique source of odor in human or animal waste.
" Zhang said, "When the air of fecal skunk skunk reaches 0.00056 ppm (one in a millionth) or 0.0030 mg/m3, the nose can identify the unique odor of fecal skunk."
" fecal skunk originated from bacterial metabolism, and its biochemical pathways are of great significance to understanding human health and related agricultural production.
anaerobic bacteria ferment aromatic amino acids into compounds that maintain a stable aromatic ring.
when bacteria living in anaerobic environments (human/animal intestines) produce these compounds, they accumulate in the host body at concentrations of submillamoles, producing physiological or pathological effects.
manure can also give off some pork products with a strange taste (pig smell), resulting in poor quality of pork or lard.
at the same time, it is also a potential lung toxin that can cause lung cancer and respiratory diseases in cattle.
, as a compound that induces mosquitoes to lay eggs, fecal skunk plays a role in promoting the occurrence and development of insect-borne infections such as filariasis, Japanese encephalitis and West Nile virus. "Despite the association between this chemical reaction and the living environment of mankind and the animal husbandry, it is challenging to understand its catalytic mechanism because it is very sensitive to oxygen.

," Zhang said.
he worked with Zhao Huimin, a professor at the University of Illinois in the United States, and Zhao Suwen, a researcher at the iHuman Research Institute at Shanghai University of Science and Technology, to focus on the study of free radical chemistry in anaerobic bacteria.
team found that bacteria produce fecal skunk by degrading tryptophan, the last step of this biochemical pathway, which relies on a previously unknown enzyme, the pyrethroid-acid depensase (IAD).
"pyridine compound de-pyridine is a free radical reaction that is chemically difficult to achieve.
as far as we know, it can only be done by IAD. Zhao Huimin, co-author of the
research, told China Science Daily in an e-mail.
, because free radicals do not have paired electrons, it is easy to get electrons and lose electrons, thus reacting with any other substance, so its life is very short, only a few milliseconds or even a few microseconds.
"But some enzymes in the evolution of life can fold free radicals into proteins by folding them, making them less short-lived and perhaps even stable, catalyzing difficult chemical reactions, such as the de-seisrosque reaction in this study."
," Zhang said.
the new glycine free radical enzyme found in this paper, IAD.
the researchers expressed the enzyme in E. coli, then fed it some acetate, and then confirmed with gas chromatography that the "reward" was skunk skunk.
the future of genetic markers, IAD can be used as a marker to determine the presence of fecal skunk.
"In future newly sequenced bacteria to determine the presence of the enzyme only need to be sequenced with the IAD known to these features to see if the residuals of the active pocket are conservative."
," Zhao Suwen told China Science Daily.
" In the new study, fecal skunk happens to be volatile, its strong odor is a sign of strong bacterial metabolism, and the body has evolved to be sensitive to the odor.
, Zhao Huimin added, "Based on the DNA sequence of IAD, people can also quickly determine the presence of fecal skunk bacteria in human and environmental samples through DNA sequencing."
" search and analysis in a vast database of bacterial genomes, the team found 12 other bacteria that produced the same IAD.
surprise, one of them is the bacteria that are separated from the gap between the teeth and gums of the human mouth.
" this explains the smell of bad breath.
," Zhang said.
free radicalase itself is very sensitive to oxygen and can only be stabilized and catalyzed in an oxygen-free environment in the intestines.
and the presence of oxygen in the mouth, at best, is only an aerobic environment, why do some bacteria have this chemical reaction? Zhang speculated that this may be because they form a biofilm.
on how to suppress this chemical reaction to stop bad breath, Zhao Suwen said, the use of antibiotics is now controversial, currently only for a certain type of bacteria antibiotics are very few, whether broad-spectrum or narrow-spectrum antibiotics can kill a variety of bacteria, change the structure of the human intestinal flora, and thus adversely affect health.
", therefore, it is best to develop good oral hygiene habits.
," she said.
blocking activity" in theory, identifying IAD would help develop an inhibitor to block its activity, thereby inhibiting the production of fecal skunk in pork or feces.
," Zhang said.
it helps to solve the problem of fecal odor and pork smell, as well as to solve the problem of large areas of pulmonary water in ruminants such as cattle and the spread of disease by attracting mosquitoes to lay eggs through fecal skunk.
identified bacteria containing IAD, they could be considered for targeted clean-up.
" can be used to drug 'bacteria or enzymes' and block the production of fecal skunk.
," Zhao said.
" such as the use of IAD-specific inhibitors.
" Zhao Huimin, for example.
he says the catalytic reaction of IAD is the last step in the energy generation process of tryptophan degradation, and a better understanding of this metabolic pathway could also help create an environment that is not suitable for the synthesis of skunk skunk.
", "We can design effective strategies, such as replacing them with congeners that produce bacteria from fecal skunks, or replacing them with genetically modified strains of missing IAD, and can be registered as probiotics, or we can block The IAD's response pathways with specific small molecule inhibitors."
," Zhao Huimin said.
, the team will continue to study the catalytic mechanism of IAD and its role in bacterial metabolism, study anaerobic enzymes associated with IAD, and further explore the small molecular compound scaratic compounds produced by anaerobic bacteria in the human microbial microbiome, which researchers believe are likely to be closely related to human health.
the unknown members of the glycol free radical protein family, the authors say, the next step will be to explore the mystery of the protein family.
it is understood that another study being carried out by the team is related to diet and farting, which involves an important body gas signaling molecule produced by intestinal bacteria.
"The molecule is associated with cancer and inflammation, and we are understanding its metabolic pathways."
," Zhang said.
Source: China Science Daily.