Chromophore-assisted light inactivation of target proteins for singularity biology.

Singularity phenomena are rare events that occur only with a probability of one in tens of thousands and yet play an important role in the fate of the entire system. Recently, an ultra-wide-field microscopy imaging systems, AMATERAS, have been developed to reliably capture singularity phenomena. However, to determine whether a rare phenomenon captured by microscopy is a true singularity phenomenon-one with a significant impact on the entire system-, causal analysis is required.

Optical inactivation of intracellular molecules by fast-maturating photosensitizing fluorescence protein, HyperNova.

Photosensitizing fluorescence protein is a promising tool for chromophore-assisted light inactivation (CALI) that enables specific oxidation and inactivation of intracellular molecules. However, a commonly used monomeric photosensitizing fluorescent protein, SuperNova, shows a low CALI efficiency due to its insufficient maturation at 37 °C, thereby limiting the application of CALI to various molecules, especially in mammalian cells. Here, we present a photosensitizing fluorescence protein, HyperNova, with markedly improved maturation at 37 °C, leading to greatly enhanced CALI efficiency.

Motor state changes escape behavior of crickets.

Animals change their behavior depending on external circumstances, internal factors, and their interactions. Locomotion state is a crucial internal factor that profoundly affects sensory perception and behavior. However, studying the behavioral impacts of locomotion state in free-moving animals has been challenging due to difficulty in reproducing quantitatively identical stimuli in freely moving animals.

Persistence of auditory modulation of wind-induced escape behavior in crickets.

Animals, including insects, change their innate escape behavior triggered by a specific threat stimulus depending on the environmental context to survive adaptively the predators' attack. This indicates that additional inputs from sensory organs of different modalities indicating surrounding conditions could affect the neuronal circuit responsible for the escape behavior. Field crickets, , exhibit an oriented running or jumping escape in response to short air puff detected by the abdominal mechanosensory organ called cerci.

Central projections of cercal giant interneurons in the adult field cricket, Gryllus bimaculatus.

The structures of neurons, such as dendrites and axonal projections, are closely related to their response properties and their specific functions in neural circuits. Identified neurons, having genetically determined morphological features and pre- and postsynaptic partners, play significant roles in specific behaviors. Giant interneurons (GIs) are identified in the terminal abdominal ganglion of the cricket as mechanosensory projection neurons and are sensitive to airflow stimulation of the cerci.

Roles of neural communication between the brain and thoracic ganglia in the selection and regulation of the cricket escape behavior.

To survive a predator's attack, prey animals must exhibit escape responses that are appropriately regulated in terms of their moving speed, distance, and direction. Insect locomotion is considered to be controlled by an interaction between the brain, which is involved in behavioral decision-making, and the thoracic ganglia (TG), which are primary motor centers. However, it remains unknown which descending and ascending signals between these neural centers are involved in the regulation of the escape behavior.

Action selection based on multiple-stimulus aspects in wind-elicited escape behavior of crickets.

Escape behavior is essential for animals to avoid attacks by predators. In some species, multiple escape responses could be employed. However, it remains unknown what aspects of threat stimuli affect the choice of an escape response.

Spatial perception mediated by insect antennal mechanosensory system.

Animals perceive their surroundings using various modalities of sensory inputs to guide their locomotion. Nocturnal insects such as crickets use mechanosensory inputs mediated by their antennae to orient in darkness. Spatial information is acquired via voluntary antennal contacts with surrounding objects, but it remains unclear whether the insects modulate behaviors mediated by other sensory organs based on that information.

Deep learning-assisted comparative analysis of animal trajectories with DeepHL.

A comparative analysis of animal behavior (e.g., male vs.

Internal state transition to switch behavioral strategies in cricket phonotaxis.

Animals employ multiple behavioral strategies for exploring food and mating partners based on both their internal state and external environment. Here, we examined how cricket phonotaxis, which was considered an innate reactive behavior of females to approach the calling song of conspecific males, depended on these internal and external conditions. Our observation revealed that the phonotaxis process consisted of two distinctive phases: wandering and approaching.

Optical Dissection of Synaptic Plasticity for Early Adaptation in Caenorhabditis elegans.

To understand neuronal information processing, it is essential to investigate the input-output relationship and its modulation via detailed dissections of synaptic transmission between pre- and postsynaptic neurons. In Caenorhabditis elegans, pre-exposure to an odorant for five minutes reduces chemotaxis (early adaptation). AWC sensory neurons and AIY interneurons are crucial for this adaptation; AWC neurons sense volatile odors, and AIY interneurons receive glutamatergic inputs from AWC neurons.

Serotonin modulates behavior-related neural activity of RID interneuron in Caenorhabditis elegans.

Animals change their behaviors in response to external stimuli, and numerous neurotransmitters are involved in these behavioral changes. In Caenorhabditis elegans, serotonin (5-HT) affects various behaviors such as inhibition of locomotion, stimulation of egg laying, and pharyngeal pumping. Previous research has shown that the neural activity of the RID interneuron increases when the worm moves forward, and the RID is necessary for sustaining forward locomotion.

Trade-off between motor performance and behavioural flexibility in the action selection of cricket escape behaviour.

To survive a predator's attack successfully, animals choose appropriate actions from multiple escape responses. The motor performance of escape response governs successful survival, which implies that the action selection in escape behaviour is based on the trade-off between competing behavioural benefits. Thus, quantitative assessment of motor performance will shed light on the biological basis of decision-making.

Effect of interactions among individuals on the chemotaxis behaviours of .

In many species, individual social animals interact with others in their group and change their collective behaviours. For the solitary nematode strain N2, previous research suggests that individuals can change the behaviour of other worms via pheromones and mechanosensory interactions. In particular, pheromones affect foraging behaviour, so that the chemotactic behaviours of individuals in a group (population) can be modulated by interactions with other individuals in the population.

Post-molting development of wind-elicited escape behavior in the cricket.

Arthropods including insects grow through several developmental stages by molting. The abrupt changes in their body size and morphology accompanying the molting are responsible for the developmental changes in behavior. While in holometabolous insects, larval behaviors are transformed into adult-specific behaviors with drastic changes in nervous system during the pupal stage, hemimetabolous insects preserve most innate behaviors whole life long, which allow us to trace the maturation process of preserved behaviors after the changes in body.

Compartmentalized cGMP Responses of Olfactory Sensory Neurons in .

Cyclic guanosine monophosphate (cGMP) plays a crucial role as a second messenger in the regulation of sensory signal transduction in many organisms. In AWC olfactory sensory neurons of , cGMP also has essential and distinctive functions in olfactory sensation and adaptation. According to molecular genetic studies, when nematodes are exposed to odorants, a decrease in cGMP regulates cGMP-gated channels for olfactory sensation.

Cysteine residues in Cu,Zn-superoxide dismutase are essential to toxicity in Caenorhabditis elegans model of amyotrophic lateral sclerosis.

Dominant mutations in Cu,Zn-superoxide dismutase (SOD1) cause a familial form of amyotrophic lateral sclerosis (ALS). A pathological hallmark of the familial ALS is the formation of mutant SOD1 aggregates, leading to the proposal that SOD1 gains toxicities through protein misfolding triggered by mutations. Nevertheless, molecular requirements for mutant SOD1 to acquire pathogenicity still remain obscure.

Targeted gene delivery in the cricket brain, using in vivo electroporation.

The cricket (Gryllus bimaculatus) is a hemimetabolous insect that is emerging as a model organism for the study of neural and molecular mechanisms of behavioral traits. However, research strategies have been limited by a lack of genetic manipulation techniques that target the nervous system of the cricket. The development of a new method for efficient gene delivery into cricket brains, using in vivo electroporation, is described here.

A method for selective ablation of neurons in C. elegans using the phototoxic fluorescent protein, KillerRed.

Specific neuron ablation with laser microbeam has been used in behavioral analysis of Caenorhabditis elegans. However, this method is hard to acquire many ablated worms, and is unable to compare behavioral changes just before and after ablation. Here, we developed an ablation method by using genetically encoded photosensitizer protein, KillerRed, which produces reactive oxygen species by green light irradiation.

Odorant-induced membrane potential depolarization of AIY interneuron in Caenorhabditis elegans.

Although some interneurons in C. elegans have been shown to have unusual region-specific Ca(2+) dynamics, the region-specific Ca(2+) and membrane potential response properties of these neurons are largely unknown due to technical limitations. In this report, we focused on one of these neurons, AIY interneuron, where Ca(2+) dynamics have been detected only in neurites, and not the soma, during odor and temperature stimulation to determine whether membrane potential and Ca(2+) are region-specific dynamics and distinct from one another.