Environmental Sciences

The Road Not Taken: Could Stress-Specific Mutations Lead to Different Evolutionary Paths?

The evolutionary trajectories of organisms are paved with mutations, which generate the raw material (genetic variation) essential for evolutionary change. In biology class, we learn that mutations are random: the probability that a mutation occurs is independent of its fitness effect (i.e., its impact on individual survival or reproduction). As Luria and Delbruck famously showed [1], bacterial mutations that confer resistance to a virus continually arise in a population before exposure to the virus; under subsequent viral infection, these mutations spread in the population.

Dynactin Subunit p150Glued Is a Neuron-Specific Anti-Catastrophe Factor

Regulation of microtubule dynamics in neurons is critical, as defects in the microtubule-based transport of axonal organelles lead to neurodegenerative disease. The microtubule motor cytoplasmic dynein and its partner complex dynactin drive retrograde transport from the distal axon.

A Sustainability Plan for the Arctic with a Focus on the Role of Diatoms

Changes over the next 50 years impacting diatoms and their role in Arctic exploration and development are examined. As Arctic ice recedes, the resulting shift in diatom species composition causes a ripple effect changing the food web, and impacting the lifestyle of Arctic people.

Arctic Ice Melt and the Ivory Gull

Reduced sea ice has made a significant impact in the Arctic ecosystem. Organisms that depend on ice are particularly sensitive to the ice’s reduction. The Ivory Gull, because they are heavily dependent on the ice, could be a key indicator species to infer changes in the ice habitat.

Applying New Technologies to Manage Solid Waste and Biosolids in Juneau

Disposal of biosolids and solid waste in an environmentally positive and cost effective method has posed a serious issue for Juneau and other Southeast communities for many years. Ever since the incineration of Juneau’s solid waste and biosolids was discontinued in 2004 and 2010, respectively, effective long­term disposal has been neglected due to cost limitations.

The Effects of Sea Ice Reduction on the Subsistence of Arctic Char (Salvelinus alpinus), Dolly Varden (Salvelinus malma) and Arctic Cisco (Coregonus autumnalis)

This paper explores the effects of climate change and induced sea ice retreat on arctic char, dolly varden and arctic cisco. These fishes are vital to the subsistence lifestyles of Inuit, Inupiat, and Inuvialuit communities living in the boroughs of northern Alaska and the Northwest Territories of Canada.

Clarifying the Mechanism of Superantigen Toxicity

Superantigens are bacterial proteins that generate a powerful immune response by binding to Major Histocompatibility Complex class II molecules on antigen-presenting cells and T cell receptors on T cells. A recent article reveals that at least one of the superantigens, staphylococcal enterotoxin B (SEB), also binds the co-stimulatory molecule CD28, suggesting that a much larger and potentially more stable complex is formed at the immunological synapse than was previously thought.

Jamb and Jamc Muscle in on Myoblast Fusion

Dashing down a track, sprinters rely on the special properties of the fast-twitch muscle fibers interspersed throughout their skeletal muscles. Meanwhile, long-distance runners are more concerned with performance of the slow-twitch muscle fibers in those same muscles. In humans, these fibers differ in the number of mitochondria they contain, but both types of muscle are formed from a cellular syncytium: many muscle cells fuse together into a multinucleate mass.

Bacterial Vaginosis Associated with Increased Risk of Female-to-Male HIV-1 Transmission: A Prospective Cohort Analysis among African Couples

Bacterial vaginosis (BV), a disruption of the normal vaginal flora, has been associated with a 60% increased risk of HIV-1 acquisition in women and higher concentration of HIV-1 RNA in the genital tract of HIV-1–infected women. However, whether BV, which is present in up to half of African HIV-1–infected women, is associated with an increase in HIV-1 transmission to male partners has not been assessed in previous studies.

Integrated Electron Microscopy: Super-Duper Resolution

Since its inception, electron microscopy (EM) has revealed that cellular membranes are organized into structurally distinct subdomains, created by localized protein and lipid assemblies to perform specific complex cellular functions. Caveolae are membrane subdomains that function as signaling platforms, endocytic carriers, sensors of membrane tension, and mechanical stress, as well as in lipid homeostasis.

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