From the molecules that drive fundamental cellular processes to the signals that influence disease, the field of molecular biology continues to reshape how scientists understand life. Read the top molecular biology stories of this year that delve into how plastic additives influence biology, how venoms affect blood vessels, and more.
A Plastic Additive Disrupts Egg Formation in Nematodes
Plastic is everywhere in modern life, from packaging and clothing to electronics and medicine, because it is cheap, durable, and versatile. However, some additives in plastics, such as benzyl butyl phthalate (BBP), which makes plastic products flexible and durable, could cause hormonal imbalance and affect reproductive health. To pinpoint the exact mechanisms by which BBP could do this, Harvard Medical School molecular and cell biologist Monica Colaiácovo and her team exposed the nematode Caenorhabditis elegans to the chemical. The researchers found that BBP caused DNA damage resulting in egg cells with the wrong number of chromosomes. The findings offer insight into the effects of BBP exposure and its consequences in animal reproduction.
Compared to control worms (left), the egg cells of BBP-treated C. elegans exhibited chromosome fragments.
Ayana Henderson
Ig Nobel Prize for a Smooth Pasta Sauce Recipe
The decision to study the physics properties of the pasta cacio e pepe came from the coauthors’ desire to make large batches of the dish for their friends.
Martina Gaiba
Italian physicists won the 2025 Physics Ig Nobel Prize, which honors research that “first makes people laugh, then makes them think,” for decoding how to make the perfect pasta sauce. The researchers used principles of phase separation to understand how cheese could form a smooth emulsion coating the pasta instead of forming stringy clumps. They found two important factors to yield a smooth sauce: temperature and starch concentration. If the temperature is too high, the proteins in the cheese denature to expose their internal structures that stick together to form clumps. Similarly, too little starch concentration gives rise to chunks of solid cheese. They found that by controlling the starch concentration and cooking temperature, they could avoid the undesirable clumps of cheese from forming.
Why Do Some People Get Premenstrual Cravings for Chocolate?
Anecdotally, many menstruators report their healthy, disciplined diet going out the window just before their period. As premenstrual emotions, fatigue, and cramps surface, so do cravings for foods rich in sugar. To understand why, Sridevi Krishnan, a nutritional biologist at the University of Arizona, and her team conducted observational studies in a handful of women. They observed that women with a higher ratio of estradiol to leptin during the premenstrual period craved sweet and carbohydrate-rich food. Moreover, those with naturally high levels of oleoylethanolamide—a lipid molecule that regulates food intake—during the first half of the cycle craved less sugary food. Additionally, while most women crave sweets, cultural aspects dictate whether they specifically crave chocolate. Overall, a combination of hormonal, neurotransmitter interactions, and cultural factors influence chocolate cravings during the premenstrual phase.
Converting Cells that Store Fat to Burn Calories
Deletion of the transcription factor KLF15 resulted in increased heat-producing fat cells in subcutaneous fat tissue.
Feldman Laboratory, University of California San Francisco
While brown adipose tissue contains cells that burn energy to release heat, white adipocyte tissue (WAT) stores fat as energy reserves for the body. However, some cells within WAT—called beige adipocytes—burn fat. Brian Feldman an academic pediatric endocrinologist at the University of California, San Francisco sought to investigate if he and his team could convert WAT into beige adipocytes. Feldman and his team had previously identified that the transcription factor Krüppel-like factor 15 (KLF15) affects adipogenesis, the process by which stem cells create fat cells. The researchers deleted the gene encoding this transcription factor in mice and observed that the animals’ subcutaneous WAT appeared brown and expressed several brown fat-associated genes. Overall, the researchers found that mature adipocytes exhibit plasticity and identified a pathway that could inform the development of therapies for obesity and metabolic diseases.
Blood Vessels-on-a-Chip Offer Insights into Deadly Snakebites
Venomous snakes inject toxins that can cause internal bleeding, or hemorrhage, when they bite. This often results in death. To study the hemorrhagic process, Vrije University Amsterdam biologist Mátyás Bittenbinder and chemist Jeroen Kool created an organ-on-a-chip model of blood vessels. By coculturing endothelial cells with extracellular matrix molecules like collagen in microfluidic channels, the researchers developed an in vitro platform that mimics the human circulatory system. They treated this model with venoms from various snake species and found that different venoms broke down blood vessels in distinct manners. Their in vitro system offers insights about the unique properties of venoms from diverse snakes and offers a platform to test different antibodies to treat snakebites.
Why is Human Scalp Hair Long?
Humans are the only mammals that have negligible body hair but extremely long hair on their heads. Scientists have hypothesized several theories to explain this. As ancient humans hunted, exposing their head to solar radiation, long scalp hair could have evolved to shield the head from the sun, reducing loss of heat and water through sweat. Moreover, human scalp hair follicles stay in the active growth phase called anagen for five to seven years, which is much longer than the anagen phase of hair follicles elsewhere on the body. Genetic factors are also at play: By studying people with unusually long hair or baldness, scientists discovered that genes such as those encoding fibroblast growth factor and Wnt Family Member 10A regulate the duration of the hair growth phase, affecting how long hair can grow.
