Remote and Persistent Alterations in Glutamate Receptor Subunit Composition Induced by Spreading Depolarizations in Rat Brain

Cellular and Molecular Neurobiology - Spreading depolarizations (SDs) are massive breakdowns of ion homeostasis in the brain’s gray matter and are a necessary pathologic mechanism for lesion...     

Invasive mollusc faunas of the River Thames exemplify biostratigraphical characterization of the Anthropocene

Profound changes to the species configuration of ecosystems globally during the 19th to 21st centuries, resulting from the introduction of neobiota, have produced a distinctive palaeontological signature in sedimentary deposits, here exemplified by those of the River Thames. Coring near Teddington Lock (ca. 4.3 m above sea level, ca. 89 km upstream from the mouth of the Thames estuary) yielded dense assemblages of shells of the invasive Asian clam Corbicula fluminea (recently invaded in 2004) and the zebra mussel Dreissena polymorpha (invaded 1824), which together accounted for 96% of individuals sampled. Population densities of C. fluminea of over 6000 individuals per m² were maintained for a depth of 1 m indicating that the Asian clam is an important biostratigraphical marker in the Thames for sedimentary deposits accumulating since 2004. The first modern European occurrence of C. fluminea was in Portugal in 1980. In 1987, the first occurrence of C. fluminea on the northern coast of South America was observed in the Caripe River, Venezuela. The non-native range of D. polymorpha was restricted to continental Europe for over 200 years until it appeared in the Great Lakes, USA, in 1986 having been transported in ballast water. Within three years, it reached populations of over 750,000 individuals per m² and it is presently recorded in 35 states. Therefore, the pan-Atlantic range expansion of D. polymorpha, coupled with the recent invasion history of C. fluminea in Venezuela and Portugal, identifies a biostratigraphical interval in sedimentary deposits forming from the early 1980s that can be correlated between Europe and the Americas.     

Isolation of Neurospora crassa bradytrophs.

A method was developed for the isolation of Neurospora bradytrophs. The bradytrophs (representing lesions in a number of pathways) were resistant to DL-p-fluorophenylalanine when growing in a leaky fashion but were sensitive when grown in the presence of their stimulating supplement.     

Retention of cryptic genes in microbial populations

Cryptic genes are silenced genes that can still be reactivated by mutation. Since they can make no positive contribution to the fitness of their carriers, it is not clear why many cryptic genes in microbial populations have not degenerated into useless DNA sequences. Hall et al. (1983) have suggested that cryptic genes have persisted because of occasional strong environmental selection for reactivated genes. The present mathematical study supports their suggestion. It shows that a cryptic gene can be retained without having any selective advantage over a useless DNA sequence, if selection for the reactivated gene occasionally occurs for a substantially long time.      

Development of amino acid uptake activity in Neurospora.

During the germination and growth of Neurospora conidia, amino acid permease systems I (neutral) and II (general) increase in specific activity. System III (basic) decreases in specific activity with the onset of germination. System I shows two peaks of activity during the logarithmic phase of growth. One peak occurs at 6 h, the other at 12 h of growth. Both peaks are abolished in the mtr mutant. Both peaks have a Km for phenylalanine of 40 muM. The peaks of system I activity appear to correlate with morphological changes.     

Utilisation of Domiciliary Dental Services

Objectives : To develop undergraduate dental student understanding of the attitudes of elderly people towards dentistry and of the barriers which prevent them from seeking treatment. Design : Each student interviewed a) an elderly person already known to them and b) an elderly person at a Day Rehabilitation Unit using a questionnaire. Students were not trained nor standardised. Setting : a) in the student's home locality, b) in a Rehabilitation Unit in Sheffield. Subjects : 161 people were interviewed with mean ages a) 78 years and b) 85 years. Main outcome measures: Perceptions of treatment need and domiciliary treatment by these elderly people. The results are summarised but not analysed because of the inherent limitations of data derived by unsupervised students. Conclusions : This educational exercise successfully engaged the studentsí minds and, for some, generated enthusiasm. They achieved valuable insight into the topic and realised that many people who inevitably have dental problems either feel that this is acceptable or do not know that they can obtain domiciliary dental care.