Molecular signals from insect antennas

Insects have a very keen sense of smell. With extremely low odor molecules in the air, it is enough for them to be identified by neurons on the antennas. Special proteins, called receptor proteins, are expressed in nerve cells to recognize flavors. Odor molecules attach to receptors and cause electronic and chemical signals to take place in the insect's brain and at the same time affect their behavior.

Besides receptors, other olfactory proteins, including enzymes and chemical sensitizing proteins, are involved. Based on molecular principles, all insects act instinctively and in a primitive way: find food, find partners, and in the case of children - find appropriate spawning sites to ensure food sources. Eat nutritious and easily digestible for generations.

The moth (Lepidotera) is a popular research object next to fruit flies. Genome of silkworm Bombyx mori is completely sequenced; however, this insect was domesticated by humans several thousand years ago, so the native species is no longer visible. On the other hand, the habitat of Manduca sexta, a North American native species is subject to the study of insect olfactory physiology, and more recently by the host - the returned Nicotiana attenuata wild tobacco into model plants for ecological research.

Tobacco worms ( Manduca sexta ) use antennas to find tobacco flowers

The genetic analysis of Manduca sexta's antennas cleared the gap in research on the direct response to insect flavors: The release of odor molecules from stressed tobacco plants was well studied, such as pollination by insects. ' But how does the smell of plants -' metaphorical voice '- go into the insect's brain? ' GS. Bill Hanson, chairman of the Department of Evolutionary Neurology at Max Planck Institute, said.

The scientists identified the transcription system - the antenna transcriptome is an important basis for the study of insect olfactory function, and completely sequenced the genes active in the antenna. Furthermore, they determined the amount of messenger RNA - mRNA of each individual - depending on each gene. Sequence information of more than 66 million nucleotides has been analyzed. Basically, the results are summarized as follows:

- Manduca sexta has 18 odorant binding proteins, OBPs and 21 chemosensory proteins and CSPs.

- Male Manduca animals possess 68 different odor receptors, each expressed in a specific type of neuron accompanied by a corresponding platelet coil in the brain, while females have 70 ' units. touch 'this. Most receptors are identified during the study.

- 69% of transcription products still cannot explain the function of a specific gene: Their role in antennas is still mysterious. According to the judgment there are many neurological mechanisms and stimulation processes in the antenna that need to be clarified. Some mRNAs are thought to be enzyme activators, such as esterified enzymes; There is also a large amount of transcriptional products that regulate gene expression, indicating that antennas can adapt to new living conditions through gene regulation.

- The antenna genetics problem does not seem to be complicated by comparing the number of genes active in the larval gut twice as much in the adult worm. Only 348 genes are preferred in males; in children is 729 genes. This may be because the way in which children live is to have fertilized eggs placed in appropriate places, such as wild tobacco, where the larvae feed.