Circadian regulation of locomotion, respiration, and arousability in adult blacklegged ticks (Ixodes scapularis).

The blacklegged tick, Ixodes scapularis, is an ectoparasitic arachnid and vector for infectious diseases, including Lyme borreliosis. Here, we investigate the diurnal activity and respiration of wild-caught and lab-reared adult ticks with long-term video recording, multi-animal tracking and high-resolution respirometry. We find male and female ticks are in a more active, more arousable state during circadian night.

Recovery from cold-induced reproductive dormancy is regulated by temperature-dependent AstC signaling.

Animals have evolved a variety of behaviors to cope with adverse environmental conditions. Similar to other insects, the fly, Drosophila melanogaster, responds to sustained cold by reducing its metabolic rate and arresting its reproduction. Here, we show that a subset of dorsal neurons (DN3s) that express the neuropeptide allatostatin C (AstC) facilitates recovery from cold-induced reproductive dormancy.

Spatially resolved measurements of ballistic and total transmission in microscale tissue samples from 450 nm to 1624 nm.

We built a simple and versatile setup to measure tissue ballistic and total transmission with customizable wavelength range, spatial resolution, and sample sizes. We performed ballistic transmission and total transmission measurements of overlying structures from biological samples . We obtained spatially resolved transmission maps to reveal transmission heterogeneity from five microscale tissue samples: skin, mouse skull bone, mosquito cuticle, wasp cuticle, and rat dura over a wide spectral range from 450 nm to 1624 nm at a spatial resolution of ∼25 m for ballistic transmission measurements and ∼50 m for total transmission measurements.

Multiphoton imaging of neural structure and activity in through the intact cuticle.

We developed a multiphoton imaging method to capture neural structure and activity in behaving flies through the intact cuticle. Our measurements showed that the fly head cuticle has surprisingly high transmission at wavelengths >900nm, and the difficulty of through-cuticle imaging is due to the air sacs and/or fat tissue underneath the head cuticle. By compressing or removing the air sacs, we performed multiphoton imaging of the fly brain through the intact cuticle.

In vivo glucose imaging in multiple model organisms with an engineered single-wavelength sensor.

Glucose is arguably the most important molecule in metabolism, and its dysregulation underlies diabetes. We describe a family of single-wavelength genetically encoded glucose sensors with a high signal-to-noise ratio, fast kinetics, and affinities varying over four orders of magnitude (1 μM to 10 mM). The sensors allow mechanistic characterization of glucose transporters expressed in cultured cells with high spatial and temporal resolution.

Correction to: A genetically encoded Ca indicator based on circularly permutated sea anemone red fluorescent protein eqFP578.

In the online version of the article [ 1 ], Figure S1 was mistakenly replaced with Figure 1.

Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms.

True physiological imaging of subcellular dynamics requires studying cells within their parent organisms, where all the environmental cues that drive gene expression, and hence the phenotypes that we actually observe, are present. A complete understanding also requires volumetric imaging of the cell and its surroundings at high spatiotemporal resolution, without inducing undue stress on either. We combined lattice light-sheet microscopy with adaptive optics to achieve, across large multicellular volumes, noninvasive aberration-free imaging of subcellular processes, including endocytosis, organelle remodeling during mitosis, and the migration of axons, immune cells, and metastatic cancer cells in vivo.

A genetically encoded Ca indicator based on circularly permutated sea anemone red fluorescent protein eqFP578.

Background: Genetically encoded calcium ion (Ca) indicators (GECIs) are indispensable tools for measuring Ca dynamics and neuronal activities in vitro and in vivo. Red fluorescent protein (RFP)-based GECIs have inherent advantages relative to green fluorescent protein-based GECIs due to the longer wavelength light used for excitation. Longer wavelength light is associated with decreased phototoxicity and deeper penetration through tissue.

Visualizing long-term single-molecule dynamics in vivo by stochastic protein labeling.

Our ability to unambiguously image and track individual molecules in live cells is limited by packing of multiple copies of labeled molecules within the resolution limit. Here we devise a universal genetic strategy to precisely control copy number of fluorescently labeled molecules in a cell. This system has a dynamic range of ∼10,000-fold, enabling sparse labeling of proteins expressed at different abundance levels.