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

Renaissance paintings, medieval archives, cloistered orchards—how one Italian scientist is uncovering secrets that could help combat a growing agricultural crisis

A century on, the country’s most beloved Thursday spectacle reaches new heights

These images from the Smithsonian Magazine Photo Contest show how communities in Mexico and beyond mark Día de los Muertos.

A clinical social worker explains the vital role of the old-fashioned rotary phone for those dealing with death and loss

It’s easy to write bugs off as pests, but consider the ways in which they have positively impacted our lives

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.

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.

A Labrador foster parent and head of a group working to better the Labrador foster care system is stressing the importance of keeping Indigenous children with Indigenous parents in their Indigenous communities.

After a year of negotiations, the postal union has given Canada Post a 72-hour strike notice. At a solidarity rally in St. John's last week, local president Craig Dyer says a strike could mean parcels — including Christmas presents — won't make it to rural communities.

The 50th Christmas Craft Fair gathered over a hundred vendors and thousands of customers in Torbay over the weekend. One family business was inspired by the early years of the fair and a passion to keep traditional crafts in style.

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.

People using the library in the Arts and Culture Centre in St. John's are being forced to use alternate entrances due to an unsafe staircase in front of the building.

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.

The L'nu Sipuk Kina'muokuom school observed Indigenous Veterans Day with an event on Friday. Students, faculty and staff got together to honour Mi’kmaw military veterans and RCMP members.

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. 

RCMP are investigating after officers discovered human remains in an abandoned, burned vehicle in Greenhill, N.S.

As Nova Scotia politicians make their fall election promises, Julie Leggett is urging them to commit to helping people on income assistance stay cool during heat waves.

Some Nova Scotia municipal leaders are defending a funding stream the federal Conservatives say they will cut if elected, calling it a "game changer."

Building highways isn't the only solution to the growing problem of traffic congestion in and around the Halifax Regional Municipality, says the head of an organization that advocates for rail-based public transit.

Elections Nova Scotia is investigating PC candidate Susan Corkum-Greek's campaign to determine whether it broke the law by handing out gift cards on Saturday outside a Tim Hortons in Lunenburg, N.S. 

The Montreal English Theatre Awards ceremony is being held this evening at Le Gesù theatre. For the community, it's a time to celebrate their achievements and resilience coming out of the pandemic, together.

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.

Two Falls (Nishu Takuatshina) was developed in Montreal by a local studio that collaborated closely with Indigenous designers and consultants.

Loved ones, friends, and people from across the city have all come together to support each other at Pastel Rita, the café Jocelyn Després helped so many call home.

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.

To understand the circuitry of the brain, it is often advantageous to visualize the processes of a single neuron or population of neurons. Identifying sites where a neuron, or neurons, originates and where it projects can allow a researcher to begin to map the circuitry underlying various processes, including sensory-guided behaviors. Furthermore, neural tracing allows one to map locations where processes terminate onto regions of the brain that may have known functions and sometimes to identify candidate upstream or downstream connections, based on proximity. Many methods of neural tracing are available; here, we focus on loading fluorescent dyes into a neuron (fluorescent dye filling). Different options for dyes exist to label neurites. Among the most versatile and easy to use are dextran amine–conjugated dyes. They fill neurons bidirectionally, not discriminating between anterograde or retrograde loading direction. Dye filling must be done in unfixed tissue, as the dye needs to move through the neurons; however, dextran amine conjugates are aldehyde-fixable and once cells have been fully loaded with dye the tissue can be fixed and subjected to immunostaining. Coupling neural tracing with immunofluorescence is a useful way to determine specific brain or ventral nerve cord (VNC) regions where a neuron projects. This protocol describes methods for loading dextran amine conjugated dyes into a sensory tissue in the mosquito to visualize sites of sensory neuron innervation in the central nervous system, as well as efferent projections to these structures. This protocol is described for Aedes aegypti, for which it was optimized, but it also works across a variety of insects.

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 natural populations of mosquitoes can play a key role in determining the underlying causes of variation in burdens of mosquito-borne disease. Aedes aegypti is the main vector of the viruses that cause dengue, chikungunya, Zika, and yellow fever, making it a high priority for laboratory study. Ae. aegypti eggs provide an ideal starting point for new laboratory colonies. Eggs can be collected using ovicups, which are small plastic cups lined with seed-germination paper and partially filled with leaf-infused H₂O. Once collected, dry eggs will remain viable for months and can be safely transported long distances back to the laboratory as long as they are properly stored. This protocol provides step-by-step instructions for preparing for collecting, storing, and hatching Ae. aegypti eggs and has successfully yielded laboratory colonies from locations across both the native and invasive range of this species.

Creating transgenic mosquitoes allows for mechanistic studies of basic mosquito biology and the development of novel vector control strategies. CRISPR–Cas9 gene editing has revolutionized gene editing, including in mosquitoes. This protocol details part of the gene editing process of Aedes aegypti mosquitoes via CRISPR–Cas9, through testing and validating single-guide RNAs (sgRNAs). Gene editing activity varies depending on the sequence of sgRNAs used, so validation of sgRNA activity should be done before large-scale generation of mutants or transgenics. sgRNA is designed using online tools and synthesized in <1 h. Once mutants or transgenics are generated via embryo microinjection, sgRNA activity is validated by quick genotyping polymerase chain reaction (PCR) and DNA sequencing.

In insects, gustatory neurons sense chemicals upon contact and directly inform many behaviors critical for survival and reproduction, including biting, feeding, mating, and egg laying. However, the taste sensory system is underexplored in many anthropophilic disease vectors such as mosquitoes, which acquire and transmit human pathogens during blood feeding from human hosts. This results in a big gap in vector biology—the study of organisms that spread disease by transmitting pathogens—because insect vectors closely interact with humans while selecting suitable individuals and appropriate bite sites for blood meals. Human sweat and skin-associated chemistries are rich in nonvolatile compounds that can be sensed by the mosquito's taste system when she lands on the skin. Taste sensory units, called sensilla, are distributed in many organs across the mosquito body, including the mouthparts, legs, and ovipositors (female-specific structures used to lay eggs). Each sensillum is innervated by as many as five taste neurons, which allow detection and discrimination between various tastants such as water, sugars, salts, amino acids, and plant-derived compounds that taste bitter to humans. Single-sensillum recordings provide a robust way to survey taste responsiveness of individual sensilla to various diagnostic and ecologically relevant chemicals. Such analyses are of immense value for understanding links between mosquito taste responses and behaviors to specific chemical cues and can provide insights into why mosquitoes prefer certain hosts. The results can also aid development of strategies to disrupt close-range mosquito–human interactions to control disease transmission. Here we describe a protocol that is curated for electrophysiological recordings from taste sensilla in mosquitoes and sure to yield exciting results for the field.

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.

Mosquito species vary in their host associations. Although some species are relative generalists, most specialize, to varying extents, on particular types of host animals. Mosquito host associations are among the most important factors that influence the transmission dynamics of mosquito-vectored pathogens, and understanding these associations can provide insight on how such pathogens move within ecosystems. Characterization of the host associations of mosquito species requires applying blood meal analysis to the largest possible sample size of mosquito blood meals. Processing large samples of mosquito blood meals can be time-consuming, especially when chain-termination sequencing is used, necessitating individual processing of each specimen. Various methods and commercially available kits and products are available for extracting DNA from mosquito blood meals. The hot sodium hydroxide and Tris (HotSHOT) method is a rapid and inexpensive method of DNA extraction that is compatible with the recovery of DNA from mosquito blood meals preserved on QIAcard Flinders Technology Associates (FTA) Classic Cards (FTA cards). FTA cards allow nucleic acids found in blood meals to be preserved easily, even in field conditions. DNA prepared using this method is suitable for polymerase chain reaction (PCR)-based blood meal analysis.

All PCR- and DNA-based blood meal analyses require host DNA from a mosquito blood meal to be effectively preserved between the time when the specimen is collected and the extraction of DNA. As soon as a mosquito ingests blood from a host animal, digestion of host cells and cellular components within the blood meal by enzymes in the mosquito midgut begins to degrade the host DNA templates that are the targets of polymerase chain reaction (PCR) amplification. Without effective preservation, host DNA is typically undetectable by PCR 48 h after feeding, because of digestion. Preservation methods for mosquito blood meals vary in their efficacy, and the logistics of fieldwork can limit the options for preservation of blood meals and maintenance of the integrity of host DNA. This protocol describes a method of blood meal preservation that is effective, convenient, and amenable to fieldwork in remote locations where cryopreservation at –20°C or –80°C may not be feasible. It uses a Flinders Technology Associates (FTA) card, which is a chemically treated card that lyses cells and allows nucleic acids to be preserved. This method is also expected to preserve the DNA or RNA of pathogens present within the engorged mosquito abdomen, including RNA viruses.

The insect eggshell is a multifunctional structure with several important roles, including generating an entry point for sperm via the micropyle before oviposition, serving as an oviposition substrate attachment surface, and functioning as a protective layer during embryo development. Eggshell proteins play major roles in eggshell tanning and hardening following oviposition and provide molecular cues that define dorsal–ventral axis formation. Precise eggshell formation during ovarian follicle maturation is critical for normal embryo development and the synthesis of a defective eggshell often gives rise to inviable embryos. Therefore, simple and accurate methods for identifying eggshell proteins will facilitate our understanding of the molecular pathways regulating eggshell formation and the mechanisms underlying normal embryo development. This protocol describes how to isolate and enrich eggshells from mature oocytes of Aedes aegypti mosquitoes and how to extract their eggshell proteins for liquid chromatography with tandem mass spectrometry (LC–MS/MS) proteomic analysis. Although this methodology was developed for studying mosquito eggshells, it may be applicable to eggs from a variety of insects. Mosquitoes are ideal model organisms for this study as their ovarian follicle development and eggshell formation are meticulously regulated by blood feeding and their follicles develop synchronously throughout oogenesis in a time-dependent manner.

In insects, oocyte resorption (oosorption) or follicular atresia is one of the key physiological processes and evolutionary strategies used to optimize reproductive fitness. Mosquitoes are ideal model organisms for studying egg maturation in arthropods, as their follicle development is initiated only following the ingestion of a blood meal, followed by a carefully orchestrated series of hormonally regulated events leading to egg maturation. A cohort of approximately 100 follicles per mosquito ovary begin developing synchronously. However, a significant fraction of follicles ultimately undergo apoptosis and oosorption, especially when available resources from the blood meal are limited. Therefore, simple, rapid, and reliable techniques to accurately evaluate follicular atresia are necessary to understand mechanisms underlying follicle development in insects. This protocol describes how to detect apoptotic follicle cells within the Aedes aegypti mosquito ovaries using a commercially available fluorescent-labeled inhibitor of caspases (FLICA). Caspases are key players in animal apoptosis. In this assay, the FLICA reagent enters the intracellular compartment of follicles in dissected mosquito ovaries and covalently binds to active caspases. The bound reagent remains within the cell and its fluorescent signal can be observed by confocal microscopy. Although this method was specifically developed for visualizing apoptotic ovarian follicles during Ae. aegypti mosquito egg development, it should be applicable to other mosquito tissues that undergo caspase-mediated program cell death in a time-dependent manner.

Transposon-mediated transgenesis has revolutionized both basic and applied studies of mosquito vectors of disease. Currently, techniques such as enhancer traps and transposon tagging, which rely on remobilizable insertional mutagenesis, are only possible with transposon-based vector systems. Here, we provide general descriptions of methods and applications of transposon-based mosquito transgenesis. The exact procedures must be adapted to each mosquito species and comparisons of some differences among different mosquito species are outlined. A number of excellent publications showing detailed and specific protocols and methods are featured and referenced.

After more than a century of searching, scientists have discovered a gene in snails that may control asymmetries inside many animals

When the National Transportation Safety Board office in Alaska first hears about a plane going down, protocol is to begin gathering information

A Two-Day Festival in the historic Arts & Industries Building brings community, artists and scholars together for a “Culture Lab”

Food is a focal point for understanding broader environmental problems. In this podcast, we learn how food buyers are influenced in surprising ways.

The ancient burial structures, strikingly similar all across Europe and the mediterranean, have puzzled scientists and historians for centuries

The Northwest Territories Power Corporation expects that by the end of March it will have generated 72 per cent of power for the North Slave region using hydro, and 28 per cent from diesel. Last year, about half the region's power was from diesel because of low water levels.

More than 50 Norman Wells residents gathered at the Royal Canadian Legion on Thursday night to voice frustrations over high heating fuel prices.

Former Dawson City Mayor Bill Kendrick has filed his defence against the town's encroachment violation lawsuit.

With president-elect Donald Trump promising to drill in Alaska's Arctic National Wildlife Refuge, the Gwich'in are preparing to fight for the Porcupine caribou herd.

Water quality guidelines for mercury are 0.02 micrograms per litre of water. Several results show that levels at four sites are far above that threshold. During the second week of October, one value close to the mine was more than seven times the acceptable level.

Yukon appeal court Justice Karen Horsman granted a temporary stay of the requirement on Friday, the latest development in an ongoing legal battle over the property between the territorial government, cabin-owner Len Tarka and tenant Eric DeLong.