School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, 92093, USA.
Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
Sci Rep. 2024 Jan 18;14(1):1631. doi: 10.1038/s41598-023-50182-5.
The resident human skin microbiome is responsible for the production of most of the human scents that are attractive to mosquitoes. Hence, engineering the human skin microbiome to synthesize less of mosquito attractants or produce repellents could potentially reduce bites and prevent the transmission of deadly mosquito-borne pathogens. In order to further characterize the human skin volatilome, we quantified the major volatiles of 39 strains of skin commensals (Staphylococci and Corynebacterium). Importantly, to validate the behavioral activity of these volatiles, we first assessed landing behavior triggered by human skin volatiles. We demonstrated that landing behavior is gated by the presence of carbon dioxide and L-(+)-lactic acid. This is similar to the combinatorial coding triggering mosquito short range attraction. Repellency behavior to selected skin volatiles and terpenes was tested in the presence of carbon dioxide and L-(+)-lactic acid. In a 2-choice landing behavior context, the skin volatiles 2- and 3-methyl butyric acids reduced mosquito landing by 62.0-81.6% and 87.1-99.6%, respectively. Similarly, the terpene geraniol was capable of reducing mosquito landing behavior by 74.9%. We also tested the potential repellency effects of terpenes in mosquitoes at short-range using a 4-port olfactometer. In these assays, geraniol reduced mosquito attraction (69-78%) to a mixture of key human kairomones carbon dioxide, L-(+)-lactic acid, and ammonia. These findings demonstrate that carbon dioxide and L-(+)-lactic acid change the valence of other skin volatiles towards mosquito landing behavior. Moreover, this study offers candidate odorants to be targeted in a novel strategy to reduce attractants or produce repellents by the human skin microbiota that may curtail mosquito bites, and subsequent mosquito-borne disease.
人体皮肤微生物组负责产生大多数对蚊子有吸引力的人体气味。因此，通过工程改造人体皮肤微生物组来减少蚊子吸引剂的合成或产生驱避剂，可能会减少叮咬并防止致命的蚊子传播病原体的传播。为了进一步描述人体皮肤挥发物组，我们量化了 39 种皮肤共生菌（葡萄球菌和棒状杆菌）的主要挥发物。重要的是，为了验证这些挥发物的行为活性，我们首先评估了人类皮肤挥发物引发的降落行为。我们证明，降落行为是由二氧化碳和 L-(+)-乳酸的存在来控制的。这类似于触发蚊子短距离吸引力的组合编码。在存在二氧化碳和 L-(+)-乳酸的情况下，测试了选定的皮肤挥发物和萜烯的驱避行为。在 2 种选择降落行为的情况下，2-和 3-甲基丁酸分别使蚊子降落减少了 62.0-81.6%和 87.1-99.6%。同样，萜烯香叶醇也能够使蚊子的降落行为减少 74.9%。我们还在短距离使用 4 端口嗅觉计测试了萜烯在蚊子中的潜在驱避效果。在这些测定中，香叶醇降低了蚊子对关键人类信息素二氧化碳、L-(+)-乳酸和氨混合物的吸引力（69-78%）。这些发现表明，二氧化碳和 L-(+)-乳酸改变了其他皮肤挥发物对蚊子降落行为的价态。此外，这项研究提供了候选气味物质，可以作为一种新策略的目标，通过人体皮肤微生物群减少吸引剂或产生驱避剂，这可能会减少蚊子叮咬和随后的蚊子传播疾病。
