Tropical climates are famously rich in biodiversity, perhaps because old lineages persist well in those regions instead of being simply replaced by new ones, or perhaps because the tropical environment promotes fast speciation. A new study of the ant family tree suggests that both these explanations may be right.
Although mutations, the driver of evolution, occur at random, a study of the bacterium Escherichia coli reveals that nature often finds the same solution to the same problem again and again. Continue reading
Testing for HIV does not simply end with the diagnosis that the virus is present in a patient; caregivers also need to track the disease’s progress to adjust ongoing treatment. Yet tests for monitoring HIV infection require sophisticated instruments, well-trained clinicians and expensive lab ware. All those are in short supply on HIV’s front line in places such as rural sub-Saharan Africa. “It’s a problem not just of cost,” explains hematologist Helen Lee of the University of Cambridge in the UK. “It’s a problem of having access.” In the last year, stripped-down standalone tests have appeared on the market, offering rural patients a cheaper, faster count of their CD4 immune cells. And in the coming months, a class of tests that measure viral load should enter routine point-of-care use, too, offering caregivers a choice of simple tools for measuring HIV infections.
An antibiotic and a protein can work together to fight radiation-induced infections better than either can manage alone. Doctors already use antibiotics to treat radiation sickness. But the addition of a protein from the immune system — bactericidal/permeability-increasing protein (BPI), which acts against poisons called endotoxins — improves the survival rate of irradiated mice, according to a study published today in Science Translational Medicine Continue reading