Sharp-eyed shooters
Video games, long maligned for promoting violence, may also have a good side: improving eyesight. A new study published by Nature Neuroscience indicates that gamers have an increased ability to detect objects in dim lighting or against a busy background.
Preferences over choices or maybe not
Economists generally assume that people make choices based on their preferences. And we do. But psychologists have long argued that the relationship goes both ways. Just as our preferences influence our choices, so too can choices influence preferences. A new study published online last week in The Journal of Neuroscience backs both sides in the debate and identifies a component of the brain's reward circuitry that seems to keep track of changing preferences.
Myocyte Repopulation? Perhaps.
Having learnt last semester that muscle cells (myocytes) do not undergo cell division but only hypertrophy (increase in cell size). This has caused heart failure after myocardial infarction (heart attack)—as the heart heals principally though the formation of scar tissue and thus, affecting contractile function.
The study by Bergmann et al. reveals that human cardiomyocytes are long-lived cells and difficult to replace, dispelling previous suggestions of widespread human cardiomyocyte repopulation. On the other hand, even though cardiomyocyte turnover is low in the adult heart, the fact that it occurs at all suggests that it can potentially be therapeutically exploited.
That journal article is so confusing. So, I guess the finding is a yes to human cardiomyocyte repopulation and a no to that as well?
Science 3 April 2009: Vol. 324. no. 5923
Renewable Source of Eggs for Female. GREAT!
For at least 50 years, the theory that female mammals do not produce new eggs after birth has been thought to explain why fertility declines with age. Not anymore.
Stem cell biologist Ji Wu and colleagues suggests that adult ovaries harbor primitive germline cells that can give rise to new eggs, or oocytes, and those in turn, when fertilized, can produce healthy offspring. If confirmed, the implications for reproductive biology and the possible treatment of infertility are enormous.
Science 17 April 2009: Vol. 324. no. 5925, p. 320
Tropical parents more likely to hear, "It's a girl!"
Wondering about the gender of your future offspring? Check your GPS. Girls are more likely to be born at tropical latitudes than in temperate or subarctic climes, according to new research. The study provides the first global look at human sex ratios and could shed light on how temperature and day length influence human reproduction.
Science 10 April 2009: Vol. 324. no. 5924, p. 163
Synonymous, Not the Same
The genetic code is redundant--many of the 20 common amino acids can be coded for by more than one codon, known as synonymous codons--which means that different DNA sequences can code for the same protein sequence. Synonymous codon usage has been thought to be determined by the abundances of iso-accepting transfer RNAs, which can play an important role in either increasing the efficiency or the accuracy of protein synthesis by the ribosome. New research suggests that initiation of translation rather than elongation, is limiting for gene expression.
Science 10 April 2009: Vol. 324. no. 5924, pp. 255 - 258
Posts
