Ne’Kiya Jackson and Calcea Johnson of Louisiana published a new study proving the Pythagorean theorem using trigonometry, a feat mathematicians long thought could not be done

A blockbuster exhibition in Paris is showcasing 500 artifacts and artworks in honor of the Surrealist Manifesto, which sparked a new artistic style that spread around the world

After a summer that tied for the country's hottest, meteorologists say an unusually warm autumn is delaying snowfall

A "staggering array" of markings have been hiding in plain sight carved into the walls of Gainsborough Old Hall, a 500-year-old home in Lincolnshire, England

When fishermen found the endangered loggerhead sea turtle off Vancouver Island in February, she was listlessly floating in a bed of kelp

This brief chapter of art history is often overlooked. Now, an exhibition in New York City makes a strong argument for the integral role played by four artists in the city of Siena

When the war ended, Allied soldiers tracked down Nicolas de Largillierre's "Portrait de femme à mi-corps" with the help of a savvy French curator who had been working for the resistance

Steve Lazarides' personal collection of prints, original works, handwritten press releases and burner phones sold at auction for around $1.4 million

The bone, described two decades after its discovery, suggests the species might have grown up to 20 percent bigger than other terror birds

The viral king penguin chick at Sea Life Melbourne Aquarium is beginning to lose his youthful down, a process that will give him his distinctive and waterproof adult plumage

Once the first primate made a break, the 42 others followed suit in a simple case of monkey-see, monkey-do

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

Some 250 volunteers transported more than 2,000 books

The actress becomes the first wheelchair user ever to take home the coveted prize at the 73rd annual award show

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

You asked, we answered

It's curtains for the NASA mission's close relationship with the satellite

The surge of hungry four-legged visitors to Belushya Guba is part of a larger trend

It fell to Belle da Costa Greene, a Black woman whose racial identity was kept secret for decades, to catalog J.P. Morgan's immense collection of books and art

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

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

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. 

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.

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.

About a thousand people stood solemnly in the rain at a cenotaph in downtown Halifax on Monday morning to pay tribute to veterans on Remembrance Day.

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.

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.

Shilei Du, 36, was charged Monday morning with the premeditated murder of his partner, Guangmei Ye, whose body was found Sunday in a residence on Fontenelle Street in Candiac, Que.

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.

The City of Montreal wants to sell more land to community organizations, housing co-ops and other groups to build off-market housing. 

Ten years after their formation, the members of The Brooks discuss how they’ve evolved and how they view their collaboration.

Quebec provincial police have confirmed that the body found in a Montreal nature park on Oct. 30 was that of kidnapping victim and cryptocurrency influencer Kevin Mirshahi.

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 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.

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.

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

By raising her son to be curious about the natural world, this mother helped shape the trajectory of the National Museum of Natural History

Newspaper editor Horace Greeley unsuccessfully ran against incumbent Ulysses S. Grant in November 1872. Twenty-four days later, he died of unknown causes at a private mental health facility