Protoplasmic Astrocytes Enhance the Ability of Neural Stem Cells to Differentiate into Neurons In Vitro

Protoplasmic astrocytes have been reported to exhibit neuroprotective effects on neurons, but there has been no direct evidence for a functional relationship between protoplasmic astrocytes and neural stem cells (NSCs). In this study, we examined neuronal differentiation of NSCs induced by protoplasmic astrocytes in a co-culture model. Protoplasmic astrocytes were isolated from new-born and NSCs from the E13-15 cortex of rats respectively. The differentiated cells labeled with neuron-specific marker β-tubulin III, were dramatically increased at 7 days in the co-culture condition. Blocking the effects of brain-derived neurotrophic factor (BDNF) with an anti-BDNF antibody reduced the number of neurons differentiated from NSCs when co-cultured with protoplasmic astrocytes. In fact, the content of BDNF in the supernatant obtained from protoplasmic astrocytes and NSCs co-culture media was significantly greater than that from control media conditions. These results indicate that protoplasmic astrocytes promote neuronal differentiation of NSCs, which is driven, at least in part, by BDNF

Infestation of shore crab gills by a free-living mussel species

Parasitic and commensal species can impact the structure and function of ecological communities and are typically highly specialized to overcome host defences. Here, we report multiple instances of a normally free-living species, the blue mussel Mytilus edulis Linnaeus, 1758, inhabiting the branchial chamber of the shore crab Carcinus maenas (Linnaeus, 1758) collected from widely separated geographical locations. A total of 127 C. maenas were examined from four locations in the English Channel, one location in the Irish Sea and two locations at the entrance of the Baltic Sea. The branchial chambers of three crabs (one from the English Channel and two from Gullmar Fjord, Sweden) were infested with mussels resembling the genus Mytilus. Sequencing at the Me15/16 locus on the polyphenolic adhesive protein gene confirmed the identity as M. edulis. Bivalve infestation always occurred in larger red male individuals. Up to 16 mussels, ranging from 2 to 11 mm in shell length, were found in each individual, either wedged between gill lamellae or attached to the branchial chamber inner wall. This is one of the first reports of a bivalve inhabiting crustacean gills and is an intriguing case of a normally free-living prey species infesting its predato

Geochemical and Microstructural Signals in Giant Clam Tridacna maxima

To validate the usability of the giant clam shell as a recorder of short-term environmental changes such as typhoons, we collected a live Tridacna maxima from Okinotori Island, Japan, on 15 June 2006. Growth increment thickness, stable isotope ratio (O-18(shell), C-13(shell)), and the barium/calcium ratio (Ba/Ca) in the T.maxima shell sample were measured and compared to Okinotori Island instrumental environmental data. In the outer layer of the shell sample, there were 3656 growth increments per year, as estimated by the O-18(shell) profile compared with sea surface temperature. The growth increments in the specimen were formed daily, and thus, we can determine the date of the sampling points of O-18(shell), C-13(shell) and the Ba/Ca ratio by counting growth increments. After typhoon approach, there is a decrease in increment thickness and some disturbed growth increments. The positive peaks in the shell Ba/Ca ratio and O-18(shell) corresponded to lower sea surface temperature caused by typhoons. These results indicated that the microstructural and geochemical record in Tridacna maxima shells could be useful for detecting past typhoon events

Review on the distribution and biology of Antarctic Monoplacophora, with first abyssal record of Laevipilina antarctica

Records of extant Monoplacophora are still scarce, often limited to single specimens or empty shells. Little is known about monoplacophoran diversity, distribution and biology. This study summarizes the present distributional knowledge of all Antarctic monoplacophorans, adding new records from the Eastern Weddell Sea. The record of Laevipilina antarctica from over 3,000 m depth extends its previously known bathymetrical range from 210 to 644 m down to abyssal depths. Special symbiosis with bacteria might contribute to this remarkable eurybathy that is unique amongst extant monoplacophoran species. L. antarctica now is known from several stations along the shelf and slope of the Eastern Weddell and Lazarev Seas. Micropilina arntzi seems limited to the shelf and upper slope of the Lazarev Sea. An undescribed Laevipilina species is known only from a single station at the upper slope of the Eastern Weddell Sea. Distributional patterns are discussed and correlated to environmental conditions and available biological information