Caffeine Consumption Helps Honey Bees Fight a Bacterial Pathogen.

Caffeine has long been used as a stimulant by humans. Although this secondary metabolite is produced by some plants as a mechanism of defense against herbivores, beneficial or detrimental effects of such consumption are usually associated with dose. The Western honey bee, Apis mellifera, can also be exposed to caffeine when foraging at Coffea and Citrus plants, and low doses as are found in the nectar of these plants seem to boost memory learning and ameliorate parasite infection in bees. In this study, we investigated the effects of caffeine consumption on the gut microbiota of honey bees and on susceptibility to bacterial infection. We performed in vivo experiments in which honey bees, deprived of or colonized with their native microbiota, were exposed to nectar-relevant concentrations of caffeine for a week, then challenged with the bacterial pathogen Serratia marcescens. We found that caffeine consumption did not impact the gut microbiota or survival rates of honey bees. Moreover, microbiota-colonized bees exposed to caffeine were more resistant to infection and exhibited increased survival rates compared to microbiota-colonized or microbiota-deprived bees only exposed to the pathogen. Our findings point to an additional benefit of caffeine consumption in honey bee health by protecting against bacterial infections. IMPORTANCE The consumption of caffeine is a remarkable feature of the human diet. Common drinks, such as coffee and tea, contain caffeine as a stimulant. Interestingly, honey bees also seem to like caffeine. They are usually attracted to the low concentrations of caffeine found in nectar and pollen of Coffea plants, and consumption improves learning and memory retention, as well as protects against viruses and fungal parasites. In this study, we expanded these findings by demonstrating that caffeine can improve survival rates of honey bees infected with Serratia marcescens, a bacterial pathogen known to cause sepsis in animals. However, this beneficial effect was only observed when bees were colonized with their native gut microbiota, and caffeine seemed not to directly affect the gut microbiota or survival rates of bees. Our findings suggest a potential synergism between caffeine and gut microbial communities in protection against bacterial pathogens.

The effects of ultra-violet laser radiation on cancer.

A group of mice implanted with squamous cell carcinoma (CA1025) and melanoma (B16) were irradiated with a cw krypton laser using 3374A (total dosage 346 j/cm2, and 660 j/cm2), and 3507A (total dosage 367 j/cm2), and a pulse N2 laser 3371a (total dosage 471 j/cm2, 660 j/cm2, and 165 j/cm2). In all groups, tumorous mice were used as controls. Regression of tumors was observed at wavelengths of 3374A and 3371A (total dosage 471 j/cm2 and 660 j/cm2). No regression was observed at 3507A. The regression in some cases was very impressive. The preliminary work on N2 laser irradiation of basal cell carcinoma (in human beings) and of BEL 7404 liver carcinoma cells in vitro and irradiation of one patient with an N2 laser performed in China will also be reported.

Laser spectrophotometer for measuring differential cross sections of biological particles.

A tunable laser spectrophotometer is described that can accurately measure the differential scattering cross sections of small particle suspensions in the visible spectral range. The instrument was calibrated using a suspension of latex spheres of known size and index of refraction. By increasing the intensity of the illuminating laser, it should be possible to study differential scattering processes of individual particles on a microsecond time scale.