Bright ideas about parasites

The Hamilton-Zuk hypothesis for parasite-mediated sexual selection in animals has generated much controversy. To resolve the arguments it will be necessary to incorporate many more details of the biology, ecology and evolution of hosts and parasites into studies of sexual selection.     

The Cost of Being Bright

Male ornaments are predicted to be a signal of the genetic quality of a male but often the relationship between ornaments and the physiological performances of males is unclear. Males of Metichnogaster cillipennis, a hover-wasp, during their courtship flights send luminous signals to females by using two abdominal reflectors. Malpighian tubules, an essential organ in the physiology of insects, participate in the building of the larger of these reflectors but at a physiological cost. By evaluating the capacity of light reflection from males during their courtship, females can assess directly the physiological quality of males.     

Bright days for yeast research

A report on the British Yeast Group Meeting, Brighton, UK, 23-25 March 2011.     

Intermittent Episodes of Bright Light Suppress Myopia in the Chicken More than Continuous Bright Light

Purpose

Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens.

Methods

Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10∶14 light∶dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5), 2 hours (n = 5), 5 hours (n = 4) or 10 hours (n = 4). Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7), 30 minutes (n = 8), 15 minutes (n = 6), 7 minutes (n = 7) or 1 minute (n = 7) periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA.

Results

Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1∶1 or 7∶7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development.

Conclusions

The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1∶1 min) provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical studies.     

Bright ideas to market your department

Nobody can do everything discussed in this article. Choose several ideas and try them. Increase your profile by letting more people in the hospital know who you are, what you do, when you do it, and how you do it. Get noticed and develop a reputation as the "go to" department. It will be worth the effort and increase your stature within the hospital. It may also help you get more staff and assume additional duties. Most of all, it will increase the respect of your department, and promote a more smoothly operating asset management system.     

Bright far-red fluorescent protein for whole-body imaging

For deep imaging of animal tissues, the optical window favorable for light penetration is in near-infrared wavelengths, which requires proteins with emission spectra in the far-red wavelengths. Here we report a far-red fluorescent protein, named Katushka, which is seven- to tenfold brighter compared to the spectrally close HcRed or mPlum, and is characterized by fast maturation as well as a high pH-stability and photostability. These unique characteristics make Katushka the protein of choice for visualization in living tissues. We demonstrate superiority of Katushka for whole-body imaging by direct comparison with other red and far-red fluorescent proteins. We also describe a monomeric version of Katushka, named mKate, which is characterized by high brightness and photostability, and should be an excellent fluorescent label for protein tagging in the far-red part of the spectrum.     

Bright artificial light produces subsensitivity to nicotine

Bright artificial light is a treatment for seasonal depression. Eleven (11) rats were exposed to bright artificial light (11,500 lux) for two consecutive weeks. The thermic response to nicotine was measured prior to light exposure and after one and two weeks of treatment. The thermic response to nicotine at baseline was -1.69 +/- 0.25 degrees C (mean +/- SEM). The thermic response to nicotine was -0.66 +/- 0.12 degrees C (p less than 0.002) after one and +0.31 +/- 0.14 degrees C (p less than 0.000025) after two weeks of light exposure. The change in temperature was different between weeks one and two (p less than 0.000025). The exposure of animals to constant light at an intensity of 300 lux did not blunt the hypothermic response to nicotine. These findings suggest that bright artificial light, like other antidepressant treatments, produces subsensitivity of a nicotinic mechanism involved in the regulation of core temperature.     

Bright artificial light produces subsensitivity to clonidine

The authors used a thermoregulation paradigm to test the hypothesis that chronic treatment with bright artificial light produces subsensitivity to the hypothermic effects of clonidine, an alpha 2-agonist. One week of treatment produced blunting of the hypothermic response to clonidine (p less than 0.00001). These findings are consistent with previous reports that somatic treatments for depression produce subsensitivity of the alpha 2-receptor.