Instruct: Given a question, retrieve passages that can help answer the question.
Query: What bacteria are responsible for smelly body odor?
Body odor is influenced by the actions of the skin flora, including members of Corynebacterium, which manufacture enzymes called lipases that break down the lipids in sweat to create smaller molecules like butyric acid. Greater bacteria populations of Corynebacterium jeikeium are for example found more in the armpits of men whereas greater population numbers of Staphylococcus haemolyticus are found in the armpits of women. This causes male armpits to give off of a rancid/cheese-like smell whereas female armpits give off a more fruity/onion-like smell.[7] Staphylococcus hominis is also known for producing thioalcohol compounds that contribute to odors.[8] These smaller molecules smell, and give body odor its characteristic aroma.[9] Propionic acid (propanoic acid) is present in many sweat samples. This acid is a breakdown product of some amino acids by propionibacteria, which thrive in the ducts of adolescent and adult sebaceous glands. Because propionic acid is chemically similar to acetic acid with similar characteristics including odor, body odors may be identified as having a vinegar-like smell by certain people. Isovaleric acid (3-methyl butanoic acid) is the other source of body odor as a result of actions of the bacteria Staphylococcus epidermidis,[10] which is also present in several strong cheese types.
Wildfires may release iron-containing compounds from the soil into small wildland streams and cause a rapid but usually temporary proliferation of iron-oxidizing bacteria complete with orange coloration, the gelatinous mats, and sulphurous odors. Higher quality personal filters typically used in backpacking/trekking can successfully remove bacteria, odor, and restore water clarity.
Human body odors influence interpersonal relationships and are involved in adaptive behaviors, such as parental attachment in infants or partner choice in adults. "Mothers can discriminate the odor of their own child, and infants recognize and prefer the body odor of their mother over that of another woman. This maternal odor appears to guide infants toward the breast and to have a calming effect." Body odor is involved in the development of infant–mother attachment and is essential to a child’s social and emotional development and evokes feelings of security. Reassurance created by familiar parental body odors may contribute significantly to the attachment process. Human body odors can also affect mate choice. Fragrances are commonly used to raise sexual attractiveness and induce sexual arousal. Researchers found that people choose perfume that interacts well with their body odor.
Smelly may refer to something with a disagreeable odor (i.e., something that smells bad). Smelly may also refer to:
Carrion begins to decay at the moment of the animal's death, and it will increasingly attract insects and breed bacteria. Not long after the animal has died, its body will begin to exude a foul odor caused by the presence of bacteria and the emission of cadaverine and putrescine.
Kramer comments that Jerry and Elaine have absorbed the body odor from the car. Elaine realizes the odor is the reason Carl didn't spend the night with her. Jerry demands that the restaurant share the cost of cleaning the car. The restaurant maître d' (Michael Des Barres) refuses. Jerry locks him inside the car, not letting him out until he agrees to pay half of the $250 fee. George discovers someone stole the video out of the car while he and Jerry were inside the restaurant.
Human perspiration is largely odorless until it is fermented by bacteria that thrive in hot, humid environments. The human underarm is among the most consistently warm areas on the surface of the human body, and sweat glands provide moisture, which when excreted, has a vital cooling effect. When adult armpits are washed with alkaline pH soap, the skin loses its acid mantle (pH 4.5 - 6), raising the skin pH and disrupting the skin barrier. As many bacteria thrive in this elevated pH environment, this makes the skin susceptible to bacterial colonization. The bacteria feed on the sweat from the apocrine glands and on dead skin and hair cells, releasing trans-3-methyl-2-hexenoic acid in their waste, which is the primary cause of body odor. Underarm hair wicks the moisture away from the skin and aids in keeping the skin dry enough to prevent or diminish bacterial colonization. The hair is less susceptible to bacterial growth and is therefore ideal for preventing the bacterial odor.
Body odor is also a potentially embarrassing grooming issue and a common reason for trimming or removing body hair. While it’s not the hair itself that smells, body odor is caused by bacteria that grow in wet conditions when air is standing still. Hair reduces the amount of air exchange and traps sweat so it can support the growth of odor-causing bacteria.
A 1996 "Popular Mechanics" article describes "jock socks odor" complaints as one of the magazine's most frequent queries with regard to automotive air conditioning systems, attributing the odor to fungal growth within the auto. The term "Dirty Sock Syndrome" is used to describe unpleasant odors that arise in building heating and cooling systems. High-efficiency heat pumps in the southeastern US have been noted as frequent offenders.
Another aspect of bacteria is the generation of body odor. Sweat is odorless however several bacteria may consume it and create byproducts which may be considered putrid by man (as in contrast to flies, for example, that may find them attractive/appealing).
Several examples are:
Myoepithelial cells form a smooth muscle lining around the secretory cells; when the muscles contract, they squeeze the secretory ducts and push out the accumulated fluid into the hair follicle. Sweat and sebum are mixed in the hair follicle and arrive mixed at the epidermal surface. The apocrine sweat is cloudy, viscous, initially odorless, and at a pH of 6–7.5. It contains water, protein, carbohydrate waste material, and NaCl. The sweat only attains its characteristic odor upon being degraded by bacteria, which releases volatile odor molecules. More bacteria (especially corynebacteria) leads to stronger odor. The presence of axillary hair also makes the odor even more pungent, as secretions, debris, keratin, and bacteria accumulate on the hairs.
Although sweating is found in a wide variety of mammals, relatively few (exceptions include humans and horses) produce large amounts of sweat in order to cool down.Sweat contributes to body odor when it is metabolized by bacteria on the skin. Medications that are used for other treatments and diet also affect odor. Some medical conditions, such as kidney failure and diabetic ketoacidosis, can also affect sweat odor. Areas that produce excessive sweat usually appear pink or white, but, in severe cases, may appear cracked, scaly, and soft.
Body odor is an important feature of animal physiology. It plays a different role in different animal species. For example, in some predator species that hunt by stalking (such as big and small cats), the absence of body odor is important, and they spend plenty of time and energy to keep their body free of odor. For other predators, which use endurance running after the visually located prey as a hunting strategy (dogs, wolves), the absence of body odor is not critical. In most animals, body odor intensifies in moments of stress and danger.
A test of olfactory abilities deemed useful in Japan employs detection of "sweaty socks" odor, along with two other odors, as a useful metric of these abilities.
Colorless urine indicates over-hydration, generally preferable to dehydration (though it can remove essential salts from the body). Colorless urine in drug tests can suggest an attempt to avoid detection of illicit drugs in the bloodstream through over-hydration.Some time after leaving the body, urine may acquire a strong "fish-like" odor because of contamination with bacteria that break down urea into ammonia. This odor is not present in fresh urine of healthy individuals; its presence may be a sign of a urinary tract infection.
Compounds which cause socks to smell intensively include:The intense odor of smelly socks commonly results from bacterial action upon sweat which accumulates due to confining footwear. The odor has also presented itself as a problem among users of prosthetics.
Back in Las Vegas, Grissom and Robbins are flipping through medical textbooks. The man's girlfriend had previously told Grissom and Nick that the man, Adam Van Der Welk, had a "sickly sweet" smell. Robbins realizes that the killer has diabetic ketoacidosis, hence the body odor. Later, Eric finds more evidence from the bacteria in the swamp that ties Mrs. Rittle's killer to the same person who killed her husband and abducted her daughter. An expensive honey was used. They look at orders and find a limo driver, Gordon Daimler, who was also the Rittles' chauffeur. Turning on the AC, Horatio finds the smell again. However, the girlfriend says he doesn't drink smelly alcohol. The treatment for diabetic ketoacidosis is insulin, and they look at buyers. They find that Daimler bought some and used it right before they found him so that he did not smell.
The main odorous compounds that contribute to axillary odor include:These malodorous compounds are formed from non-odoriferous precursors that are secreted from apocrine glands and converted by various enzymes expressed in skin surface bacteria. The specific skin surface bacteria responsible are mainly "Staphylococcus" and "Corynebacterium" species.
Some living algae and bacteria, also produce odorous chemicals, particularly certain (cyanobacteria) (previously classed as blue-green algae) such as "Anabaena". The most well-known of these odor-causing chemicals are MIB (2-methylisoborneol) and geosmin. They give a musty or earthy odor that can be quite strong. Eventual death of the cyanobacteria releases additional gas that is trapped in the cells. These chemicals are detectable at very low levels, in the parts per billion range, and are responsible for many "taste and odor" issues in drinking water treatment and distribution. Cyanobacteria can also produce chemical toxins that have been a problem in drinking water.
Sodium bicarbonate is used as an inexpensive home remedy for the prevention of foot odor. However, the extent of the antimicrobial effect on the odor-causing bacteria is unclear. A solution of 10% household bleach in 90% water kills the odor-causing bacteria. A brush can be used to clean between the toes. Swabbing feet twice daily with isopropyl alcohol is another home remedy.
What causes a substance to smell unpleasant may be different from what one perceives. For example, perspiration is often viewed as having an unpleasant odor, but it is odorless. It is the bacteria in the perspiration that cause the odor.
The biochemistry of body odor pertains to the chemical compounds in the body responsible for body odor and their kinetics.
In 2010, the self-described historian Don Shelton questioned the methods by which Smellie performed his research. In the "Journal of the Royal Society of Medicine" he suggested that Smellie and his collaborator and later competitor William Hunter were responsible for multiple murders of pregnant women in order to gain access to corpses for anatomical dissection and physiological experimentation. Due to the inadequate match between supply and demand of corpses, scientists had to find other means, often requiring illegal methods, to obtain access. Shelton proposed that these two physicians used what would later be named "burking", after murderer William Burke, who killed 16 people in collusion with William Hare, selling the bodies to anatomist Dr. Robert Knox. He indicated that grave robbing was not a sufficient method by which obstetricians could access the specific type of tissue required for testing and dissection. In 1755, there was questioning of Smellie's access to corpses. Many of the accusations came from competitors, and fearing trial and even execution, Smellie stopped his work for several years in an effort to quash the suspicion that had been raised.
Body odor encompasses axillary (underarm) odor and foot odor. It is caused by a combination of sweat gland secretions and normal skin microflora. In addition, androstane steroids and the ABCC11 transporter are essential for most axillary odor. Body odor is a complex phenomenon, with numerous compounds and catalysts involved in its genesis. Secretions from sweat glands are initially odorless, but preodoriferous compounds or malodor precursors in the secretions are transformed by skin surface bacteria into volatile odorous compounds that are responsible for body malodor. Water and nutrients secreted by sweat glands also contribute to body odor by creating an ideal environment for supporting the growth of skin surface bacteria.
Odor perception is a complex process involving the central nervous system and can evoke psychological and physiological responses. Because the olfactory signal terminates in or near the amygdala, odors are strongly linked to memories and can evoke emotions. The amygdala participates in the hedonic or emotional processing of olfactory stimuli. Odors can disturb our concentration, diminish productivity, evoke symptoms, and in general increase a dislike for an environment. Odors can impact the liking for a person, place, food, or product as a form of conditioning. Memories recalled by odors are significantly more emotional and evocative than those recalled by the same cue presented visually or auditorily. Odors can become conditioned to experiential states and when later encountered have directional influences on behavior. Doing a frustrating task in a scented room decreases performance of other cognitive tasks in the presence of the same odor. Nonhuman animals communicate their emotional states through changes in body odor, and human body odors are indicative of emotional state.