Kagawa University

About: Kagawa University is a education organization based out in Takamatsu, Japan. It is known for research contribution in the topics: Cancer & Population. The organization has 6028 authors who have published 11918 publications receiving 224111 citations. The organization is also known as: Kagawa Daigaku.

The first skull of Australopithecus boisei

Abstract: Australopithecus boisei was first described from a cranium recovered in 1959 from Olduvai Gorge, Tanzania1,2. This and subsequent finds, mostly from Kenya's Turkana basin3,4,5, resulted in its characterization as a specialized Australopithecus species with a hyper-robust masticatory apparatus2,4,6. A distinct A. boisei facial morphology has been emphasized to differentiate robust Australopithecus lineages from East and South Africa6. A preference for closed and/or wet habitats has been hypothesized7. Here we report some new A. boisei specimens, including the taxon's first cranium and associated mandible, from Konso, Ethiopia. These fossils extend the known geographical range of A. boisei. They provide clear evidence for the coexistence of A. boisei and Homo erectus within a predominantly dry grassland environment. The A. boisei specimens from Konso demonstrate considerable morphological variation within the species. The unexpected combination of cranial and facial features of this skull cautions against the excessive taxonomic splitting of early hominids based on morphological detail documented in small and/or geographically restricted samples.

Female multiple mating as a genetic bet-hedging strategy when mate choice criteria are unreliable

Abstract: Female multiple mating (or polyandry) is considered to act as a genetic bet-hedging mechanism, by which females can reduce the assessment error in regard to mates’ genetic quality when only uncertain information is available. In spite of frequent verbal arguments, no theoretical examination has been carried out to determine the effectiveness of bet-hedging by multiple mating. In the present paper, I show that three factors, female population size, remating costs and environmental fluctuation, all affect the effectiveness of bet-hedging. A mathematical model predicts that bet-hedging effectively works only in small populations, and computer simulations were used to confirm this prediction. The results of simulations differed according to the degree of environmental fluctuation. In relatively stable environments, if there is no remating cost, the fixation probability of a multiple mating strategy is slightly higher than that of a single mating strategy, independent of female population size. However, with very slight fitness costs, multiple mating drastically loses its advantage as population size increases, and almost always becomes extinct within large populations. This means that the evolution of polyandry solely by the mechanism of bet-hedging is unlikely in stable environments. However, in unpredictable environments, or when negative frequency-dependent selection on fitness-related loci is introduced, a multiple mating strategy is sometimes successful against a single mating strategy, even if it entails a small fitness cost. Therefore, female multiple mating may possibly evolve only in these limited conditions. In most cases, some deterministic mechanisms such as postcopulatory sperm selection by multiply mated females (or direct ‘material’ benefits) are more reasonable as the evolutionary causes of polyandry.

Rosmarinic acid extract for antioxidant, antiallergic, and α-glucosidase inhibitory activities, isolated by supramolecular technique and solvent extraction from Perilla leaves.

Abstract: Rosmarinic acid extract with potent biological activities was successfully isolated by supramolecular technique and solvent extraction from Perilla leaves. By the supramolecular complex which was formed from flavocommelin and Perilla leaf extract as initial materials, the supernatant containing rosmarinic acid was isolated. Rosmarinic acid extract (62.9 ± 4.5% purity) was partly purified by partitioning ethyl acetate and water. Rosmarinic acid extract exhibited high total phenolic content of 433.9 ± 58.6 μg/mg of gallic acid equivalent, effective DPPH radical scavenging activity (SC50 of 5.5 ± 0.2 μg/mL), antiallergic activity (IC50 of 52.9 ± 6.7 μg/mL), and α-glucosidase inhibitory activity (IC50 of 0.23 ± 0.01 mg/mL). Rosmarinic acid extract shows high potential for diabetes mellitus and allergy treatments by inhibiting α-glucosidase activity and measuring β-hexosaminidase, related to life-style disease.