Pathogens are more common in polar bears living in the Chukchi Sea now than they were three decades ago, a new study suggests—but it's not yet clear what that means for the mammals' health

The looming sculpture features a small camera above an eight-foot-tall screen, which displays live video from Lithuania, Poland and Ireland

Using high-res scans, a researcher uncovered scribbled etchings likely made by the British poet and artist while working as a teenage apprentice engraver in the 1770s

Colossal Biosciences reports it extracted DNA and RNA from the Tasmanian tiger specimen, a key step forward in its effort to create a modern proxy of the extinct species. Other scientists are calling for data to back up the claim

The banana duct-taped to a wall was created to be a "reflection on what we value." An upcoming auction may deliver an answer

A team of roboticists, paleontologists and biologists are building robots to simulate crucial evolutionary developments that can’t be tested with static fossils

By analyzing an old lidar survey, researchers found evidence of more than 6,500 ancient structures in a previously unexplored area of Campeche

Ai-Da creates art using A.I. algorithms, cameras and robotic arms. Her abstract painting will be the first-ever artwork made by a humanoid robot to be sold at Sotheby's

A new study suggests the seismic energy traveled outward from a previously unmapped fault, emanating from the hypocenter in bouncing waves that shook distant areas

The fragile 18th-century containers, which likely held alcoholic beverages that were shared among passengers and crew members, survived for centuries at the bottom of the Atlantic Ocean

Introduced in 1934, the federal duck stamp contest has raised more than $1.2 billion and protected at least 6.5 million acres across the nation. Now, an art exhibition at Connecticut’s Bruce Museum honors the competition’s history

Work is underway to restore the Bray School, which will be dedicated in a ceremony on Friday. The historic building in Colonial Williamsburg will open its doors in the spring of 2025

Unlike other birds, which get pigments from their diets, parrots produce their own—but scientists never fully understood the underlying mechanisms, until now

Babies who were conceived and born during the period of rationing in the United Kingdom were less likely to develop certain diseases as adults, a new study finds

Born October 30 to parents Gloria and Otto at the Edinburgh Zoo in Scotland, the hippo is already gaining popularity, following in the footsteps of viral sensation Moo Deng

The 3,800-year-old site near the city of Luxor holds the remains of 11 individuals, who may have been members of the same family. Researchers think the tomb was used for several generations

The beloved reptile in Australia died last weekend and was thought to be up to 120 years old, though that age is only an estimate. Research on his bones might reveal a more exact number

It's not the first time savvy entrepreneurs have marketed canned air to tourists. Similar products have been sold at vacation destinations for decades

Lula the bear and Simba the lion have been evacuated to a wildlife shelter in Jordan

‘Our goal is to provide full flexibility, 24/7,’ one resident said. ‘If you want to cut the lawn at 4 a.m., then you do it.’

Sharks have been losing teeth for 400 million years. Here’s a guide to uncovering some of these plentiful fossils across the country

Eight years into living in Longyearbyen, on the Norwegian archipelago of Svalbard, I embrace the seasonal plunge into total darkness

These amazing images from the Smithsonian Magazine Photo Contest show the Arctic animals at their fierce but adorable best

Getting the perfect shot requires great timing, the right equipment and nerves of steel

These grounded planes in the Congo have captured the imagination of these children

In the 1960s, a vaccine for chlamydia made patients more susceptible to chlamydia. Now scientists know why

"Fascinating, Captain"

As of last Wednesday, at least 3,500 sea turtles have been rescued from freezing waters in the midst record-breaking winter storm

The trend is a result of women deciding to have children later in life and the use of medically assisted reproduction methods

In a twist befitting its pages, the satirical, anti-establishment publication that delivered laughs and hijinks to generations of young readers gets the respect it always deserved with a new museum exhibition

Adverse weather has cancelled ferry crossings between Newfoundland and Labrador and Nova Scotia heading into the long weekend.

Newfoundland filmmaker Justin Simms is releasing his latest film called Sons. It was prompted by the birth of his son and left him wondering how traditional masculine behaviour is learned.

Nellie Winters is 87. From the time she was a child, her hands and mind have been busy pursuing her love of Inuit art and craft.

Bombardier control box recovered during second dive to a World War 2 bomber at the bottom of Gander Lake.

Large crowds came together at city hall in Corner Brook to lay wreaths and honour veterans on Monday. The ceremony portion was completed with a playing of the Last Post.

Hundreds congregated in downtown St. John's Monday morning to pay tribute to Newfoundland and Labrador's fallen soldiers, and honoured the dead for the first time at the newly refurbished National War Memorial and tomb of the Unknown Solider. 

Nurses' union president Yvette Coffey says more must be done to ensure young nurses stay in the province. Newfoundland and Labrador Health Services says work is underway to match students with job openings.

Ashley Hickey, a parent of a kid with celiac disease, is concerned that Nova Scotia's new school program does not offer any 100 per cent guaranteed gluten-free options.

A researcher studying the rise of extremism in Atlantic Canada warns Ku Klux Klan Halloween costumes are just one example of an insidious effort by far-right groups to normalize hateful attitudes.

Independent Elizabeth Smith-McCrossin is back on the campaign trail in Cumberland North, but opponents say the riding would be better represented by an MLA from an official party. 

The Société de transport de Montréal (STM) has established a non-urgent text line for transit users to signal security issues in the Metro network.

The union representing dockworkers in Montreal says Canada's labour minister forcing its members back to work at ports in Montreal and Quebec City marks a "dark day for workers' rights."

Amid rapid global advances and deployment of artificial intelligence technologies, the federal government has invested millions to combine the minds of three existing institutes into one that can keep an eye on potential dangers ahead.

Mosquito-borne disease is a major global public health issue. One path toward the development of evidence-based strategies to limit mosquito biting is the study of the mosquito nervous system—in particular, the sensory systems that drive biting behavior. The central nervous system of insects consists of the brain and the ventral nerve cord. Here, we describe a protocol for dissecting, immunofluorescent labeling, and imaging both of these structures in the mosquito. This protocol was optimized for Aedes aegypti and works well on Anopheles gambiae tissue. It has not been tested in other mosquito species, but we anticipate that it would work on a range of mosquitoes, and, if not, our protocol will provide a starting point from which to optimize. Notably, a limited number of antibodies cross-react with Ae. aegypti proteins. This protocol is intended for use with validated antibodies and can also be used to test new antibodies as they are generated. It has been successfully used to visualize protein tags, such as green fluorescent protein, that have been introduced into the mosquito to amplify or detect their presence.

Laboratory study of field-collected mosquitoes can allow researchers to better understand the ways variation within and among mosquito populations shapes burdens of mosquito-borne disease. The Anopheles gambiae complex comprises the most important vectors of malaria, but it can be challenging to keep in the laboratory. For some species of mosquitoes, especially An. gambiae, it is very difficult to bring viable eggs into the laboratory. Instead, it is preferable to collect larvae or pupae and then transport them as carefully as possible back to the laboratory. This simple protocol allows a researcher to start new laboratory colonies from larvae or pupae collected from natural breeding sites or proceed directly to their planned experiments. The use of natural breeding sites provides additional reassurance that the resulting colonies are representative of natural populations.

Genetically encoded calcium indicators (GECIs) allow for the noninvasive evaluation of neuronal activity in vivo, and imaging GECIs in Drosophila has become commonplace for understanding neural functions and connectivity in this system. GECIs can also be used as read-outs for studying sleep in this model organism. Here, we describe a methodology for tracking the activity of neurons in the fly brain using a two-photon (2p) microscopy system. This method can be adapted to perform functional studies of neural activity in Drosophila under both spontaneous and evoked conditions, as well as during spontaneous or induced sleep. We first describe a tethering and surgical procedure that allows survival under the microscopy conditions required for long-term recordings. We then outline the steps and reagents required for optogenetic activation of sleep-promoting neurons while simultaneously recording neural activity from the fly brain. We also describe the procedure for recording from two different locations—namely, the top of the head (e.g., to record mushroom body calyx activity) or the back of the head (e.g., to record central complex activity). We also provide different strategies for recording from GECIs confined to the cell body versus the entire neuron. Finally, we describe the steps required for analyzing the multidimensional data that can be acquired. In all, this protocol shows how to perform calcium imaging experiments in tethered flies, with a focus on acquiring spontaneous and induced sleep data.

Sleep studies in Drosophila melanogaster rely mostly on behavioral read-outs to support molecular or circuit-level investigations in this model. Electrophysiology can provide an additional level of understanding in these studies to, for example, investigate changes in brain activity associated with sleep manipulations. In this protocol, we describe a procedure for performing multichannel local field potential (LFP) recordings in the fruit fly, with a flexible system that can be adapted to different experimental paradigms and situations. The approach uses electrodes containing multiple recording sites (16), allowing the acquisition of large amounts of neuronal activity data from a transect through the brain while flies are still able to sleep. The approach starts by tethering the fly, followed by positioning it on an air-supported ball. A multichannel silicon probe is then inserted laterally into the fly brain via one eye, allowing for recording of electrical signals from the retina through to the central brain. These recordings can be acquired under spontaneous conditions or in the presence of visual stimuli, and the minimal surgery promotes long-term recordings (e.g., overnight). Sleep and wake can be tracked using infrared cameras, which allow for the measurement of locomotive activity as well as microbehaviors such as proboscis extensions during sleep. The protocol has been optimized to promote subject survivability, which is an important factor when performing long-term (~16-h) recordings. The approach described here uses specific recording probes, data acquisition devices, and analysis tools. Although it is expected that some of these items might need to be adapted to the equipment available in different laboratories, the overall aim is to provide an overview on how to record electrical activity across the brain of behaving (and sleeping) flies using this kind of approach and technology.

The technique of visualizing axon pathways in the embryonic ventral nerve cord using antibody labeling has been fundamental to our understanding of the genetic and developmental mechanisms underlying nervous system wiring in Drosophila. High-resolution microscopic examination of the ventral nerve cord remains an essential component of many experiments in Drosophila developmental neuroscience. Although it is possible to examine the ventral nerve cord in intact whole-mount embryos, to collect the highest-quality images it is often useful to isolate the nervous system away from the other embryonic tissues through embryo dissection. This protocol describes methods for dissecting ventral nerve cords from Drosophila embryos that have been fixed and stained via immunofluorescence or horseradish peroxidase (HRP) immunohistochemistry. The process of making fine dissection needles for this purpose from electrolytically sharpened tungsten wire is also described. Dissected and mounted ventral nerve cords can be examined and imaged using a variety of microscopy techniques including differential interference contrast (DIC) optics, epifluorescence, or confocal microscopy.

The Drosophila embryonic central nervous system has been used for decades as a model for understanding the genetic regulation of axon guidance and other aspects of neural development. Foundational studies using antibody staining to examine the embryonic ventral nerve cord in wild-type and mutant animals led to the discovery of evolutionarily conserved genes that regulate fundamental aspects of axon guidance, including midline crossing of axons. The development of the regular, segmentally repeating structure of axon pathways in the ventral nerve cord can illustrate basic principles of axon guidance to beginning students and can also be used by expert researchers to characterize new mutants, detect genetic interactions between known genes, and precisely quantify variations in gene function in engineered mutant lines. Here, we describe a protocol for collecting and fixing Drosophila embryos and visualizing axon pathways in the embryonic ventral nerve cord using immunofluorescence or immunohistochemical staining methods. As embryogenesis in Drosophila takes ~24 h to complete, a 1-d collection yields embryos representing all stages of development from newly fertilized through ready-to-hatch larvae, allowing investigation of multiple developmental events within a single batch of collected embryos. The methods described in this protocol should be accessible to introductory laboratory courses as well as seasoned investigators in established research laboratories.

Mosquitoes take blood meals from a diverse range of host animals and their host associations vary by species. Characterizing these associations is an important element of the transmission dynamics of mosquito-vectored pathogens. To characterize mosquito host associations, various molecular techniques have been developed, which are collectively referred to as blood meal analysis. DNA barcoding has diverse biological applications and is well-suited to mosquito blood meal analysis. The standard DNA barcoding marker for animals is a 5' fragment of the cytochrome c oxidase I (COI) gene. A major advantage of this marker is its taxonomic coverage in DNA sequence reference databases, making it feasible to identify a wider range of mosquito host species than with any other gene. However, the COI gene contains high sequence variation at potential priming sites between vertebrate orders. Coupled with the need for primer sequences to be mismatched with mosquito priming sites so that annealing to mosquito DNA is inhibited, it can be difficult to design primers suitable for blood meal analysis applications. Several primers are available that perform well in mosquito blood meal analysis, annealing to priming sites for most vertebrate host taxa, but not to those of mosquitoes. Because priming site sequence variation among vertebrate taxa can cause amplification to fail, a hierarchical approach to DNA barcoding-based blood meal analysis can be applied. In such an approach, no single primer set is expected to be effective for 100% of potential host species. If amplification fails in the initial reaction, a subsequent reaction is attempted with primers that anneal to different priming sites, and so on, until amplification is successful.