Parental environment changes the dormancy state and karrikinolide response of Brassica tournefortii seeds.

BACKGROUND AND AIMS: The smoke-derived chemical karrikinolide (KAR(1)) shows potential as a tool to synchronize the germination of seeds for weed management and restoration. To assess its feasibility we need to understand why seeds from different populations of a species exhibit distinct responses to KAR(1). Environmental conditions during seed development, known as the parental environment, influence seed dormancy so we predicted that parental environment would also drive the KAR(1)-responses of seeds. Specifically, we hypothesized that (a) a common environment will unify the KAR(1)-responses of different populations, (b) a single population grown under different environmental conditions will exhibit different KAR(1)-responses, and (c) drought stress, as a particular feature of the parental environment, will make seeds less dormant and more responsive to KAR(1). METHODS: Seeds of the weed Brassica tournefortii were collected from four locations in Western Australia and were sown in common gardens at two field sites, to test whether their KAR(1)-responses could be unified by a common environment. To test the effects of drought on KAR(1)-response, plants were grown in a glasshouse and subjected to water stress. For each trial, the germination responses of the next generation of seeds were assessed. KEY RESULTS: The KAR(1)-responses of seeds differed among populations, but this variation was reduced when seeds developed in a common environment. The KAR(1)-responses of each population changed when seeds developed in different environments. Different parental environments affected germination responses of the populations differently, showing that parental environment interacts with genetics to determine KAR(1)-responses. Seeds from droughted plants were 5 % more responsive to KAR(1) and 5 % less dormant than seeds from well-watered plants, but KAR(1)-responses and dormancy state were not intrinsically linked in all experiments. CONCLUSIONS: The parental environment in which seeds develop is one of the key drivers of the KAR(1)-responses of seeds.

M. tuberculosis molecular variation in CNS infection: evidence for strain-dependent neurovirulence.

OBJECTIVE: To determine the molecular diversity among Mycobacterium tuberculosis isolates associated with central nervous system tuberculosis (CNS TB) in a defined cohort of HIV uninfected patients. DESIGN/METHODS: A retrospective analysis was performed of clinical and laboratory data for all patients with CNS TB diagnosed in Manitoba, Canada, between 1979 and 1996. Restriction fragment-length polymorphisms (RFLP) of archival isolates of M. tuberculosis from CNS TB patients were determined and interpreted against the frequency of different isolates from all TB patients in the years 1992 to 1996. RESULTS: Among 2,334 patients with active TB, CNS TB was diagnosed in 42 (1.8%); meningitis with or without tuberculoma in 76%; and tuberculoma alone in 24%. CNS TB patients were significantly more likely to be young (<40 years old), female, and of Aboriginal origin. Morbidity (fixed/recurrent CNS deficit) rate was 29% and mortality rate was 26%. An adverse outcome, either morbidity or mortality, was significantly more common in those with meningitis. RFLP analysis of isolates (n=19) from CNS TB patients revealed 13 distinct restriction patterns with a predominance of the type 1 pattern (n=6). The frequency of type 1 restriction pattern was significantly greater in patients with CNS TB compared to all TB patients in Manitoba. CONCLUSIONS: CNS TB continues to have a high morbidity and mortality despite modern methods of detection and treatment. Although several strains of M. tuberculosis cause CNS TB, the current study suggests that the occurrence of CNS TB may be strain-dependent.

Video recording.

Two video techniques are commonly used for biomedical monitoring. The simplest technique uses 2 or 3 video cameras with a special-effects generator. The more advanced method uses one video camera with a reformatter, a special-effects generator and a time-code generator. The main components of a video recording system are the camera, tape recorder, monitor, special-effects generator, reformatter, audio system and time-code generator. Video recordings can be edited electronically, but the quality of the copies is dependent on the type of editing equipment and the technical expertise available. Video recording has helped to improve the diagnosis and treatment of seizures and has been widely used in clinical epilepsy research. Video monitoring is now generally available in large medical centers for the diagnosis of difficult patients.

Monitoring at the National Institute of Neurological and Communicative Disorders and Stroke.

Intensive monitoring (prolonged, telemetered EEG recording, video tape recording, and plasma drug level monitoring) has an integral role in the correct diagnosis and treatment of patients with intractable epilepsy or suspected epilepsy. The intensive monitoring unit at the Clinical Epilepsy Section, NINCDS, exemplifies a well-integrated system for clinical epilepsy research. The resulting library of video taped seizures is a valuable resource for teaching and the production of films on epilepsy.