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Cell Aug 2022Aedes aegypti mosquitoes are a persistent human foe, transmitting arboviruses including dengue when they feed on human blood. Mosquitoes are intensely attracted to body...
Aedes aegypti mosquitoes are a persistent human foe, transmitting arboviruses including dengue when they feed on human blood. Mosquitoes are intensely attracted to body odor and carbon dioxide, which they detect using ionotropic chemosensory receptors encoded by three large multi-gene families. Genetic mutations that disrupt the olfactory system have modest effects on human attraction, suggesting redundancy in odor coding. The canonical view is that olfactory sensory neurons each express a single chemosensory receptor that defines its ligand selectivity. We discovered that Ae. aegypti uses a different organizational principle, with many neurons co-expressing multiple chemosensory receptor genes. In vivo electrophysiology demonstrates that the broad ligand-sensitivity of mosquito olfactory neurons depends on this non-canonical co-expression. The redundancy afforded by an olfactory system in which neurons co-express multiple chemosensory receptors may increase the robustness of the mosquito olfactory system and explain our long-standing inability to disrupt the detection of humans by mosquitoes.
Topics: Aedes; Animals; Humans; Ligands; Odorants; Olfactory Receptor Neurons
PubMed: 35985288
DOI: 10.1016/j.cell.2022.07.024 -
Ostomy/wound Management May 2018Little is known about the nutritional status and dietary habits of persons with an intestinal stoma, and no specific dietary guidelines have been established. A...
Little is known about the nutritional status and dietary habits of persons with an intestinal stoma, and no specific dietary guidelines have been established. A cross-sectional study was conducted among patients of a Stoma Patient Health Care Service in Juiz de Fora, Brazil, to compare the nutritional status of persons with an ileostomy or colostomy and to evaluate which foods are avoided most frequently and why. Anthropometric measurements (weight, height, arm circumference, and triceps and subscapular skinfold thickness) and body fat were assessed. Habitual dietary intake (energy, protein, carbohydrate, fiber, fat, calcium, iron, sodium, potassium, thiamin, riboflavin, vitamin B6, vitamin B3 [niacin], and vitamin B12) was assessed using a validated quantitative food frequency questionnaire. Foods avoided and reasons for avoidance (increased odor, increased gas, increased output, constipation, appliance leakage, and feelings regarding leaving home) were assessed. All data were collected without personal identifiers and stored in electronic files. Data were analyzed descriptively, and the Student's t test or Mann-Whitney test was used to compare the groups. Chi-squared analysis with Yates' continuity correction or Fisher's exact test was employed to examine the differences in the frequency of avoided foods by reasons for avoidance between the 2 groups. Of the 103 participants (52 [50.5%] men, 51 [49.5%] women; mean age 60.5 ± 12.9 years); 63 (61.2%) had a colostomy and 40 (38.8%) had an ileostomy. For both groups combined, time since surgery ranged from 1 to 360 months. Anthropometric measurements and body composition did not suggest nutritional deficiencies and did not differ significantly between groups. Persons with an ileostomy had a significantly lower fat and niacin intake than persons with a colostomy (P <.05). No other dietary intake differences were observed. Avoiding foods due to appliance leakage was more common among participants with an ileostomy (8, 20%) than a colostomy (3, 4.8%), and vegetables and fruits were reported as the most problematic foods. None of the other cited reasons was significantly different. The results of this study confirm that many persons with a stoma adjust their dietary intake and avoid certain foods which, especially in persons with an ileostomy, may increase their risk for nutritional deficiencies. Additional research to assess dietary intake and nutritional status variables as well as patient needs is needed to facilitate the development of specific nutritional status monitoring and dietary recommendations for persons with an ileostomy or colostomy.
Topics: Adult; Aged; Aged, 80 and over; Anthropometry; Brazil; Colostomy; Cross-Sectional Studies; Diet; Diet Therapy; Female; Humans; Ileostomy; Male; Middle Aged; Nutritional Status; Surveys and Questionnaires
PubMed: 29847308
DOI: No ID Found -
Science Advances Jun 2022Nonhuman terrestrial mammals sniff themselves and each other to decide who is friend or foe. Humans also sniff themselves and each other, but the function of this is...
Nonhuman terrestrial mammals sniff themselves and each other to decide who is friend or foe. Humans also sniff themselves and each other, but the function of this is unknown. Because humans seek friends who are similar to themselves, we hypothesized that humans may smell themselves and others to subconsciously estimate body odor similarity, which, in turn, may promote friendship. To test this, we recruited nonromantic same-sex friend dyads and harvested their body odor. We found that objective ratings obtained with an electronic nose, and subjective ratings obtained from independent human smellers converged to suggest that friends smell more similar to each other than random dyads. Last, we recruited complete strangers, smelled them with an electronic nose, and engaged them in nonverbal same-sex dyadic interactions. We observed that dyads who smelled more similar had more positive dyadic interactions. In other words, we could predict social bonding with an electronic nose. We conclude that there is indeed chemistry in social chemistry.
PubMed: 35749498
DOI: 10.1126/sciadv.abn0154