Comparative genomics of Eucalyptus and Corymbia reveals low rates of genome structural rearrangement.

BACKGROUND: Previous studies suggest genome structure is largely conserved between Eucalyptus species. However, it is unknown if this conservation extends to more divergent eucalypt taxa. We performed comparative genomics between the eucalypt genera Eucalyptus and Corymbia. Our results will facilitate transfer of genomic information between these important taxa and provide further insights into the rate of structural change in tree genomes. RESULTS: We constructed three high density linkage maps for two Corymbia species (Corymbia citriodora subsp. variegata and Corymbia torelliana) which were used to compare genome structure between both species and Eucalyptus grandis. Genome structure was highly conserved between the Corymbia species. However, the comparison of Corymbia and E. grandis suggests large (from 1-13 MB) intra-chromosomal rearrangements have occurred on seven of the 11 chromosomes. Most rearrangements were supported through comparisons of the three independent Corymbia maps to the E. grandis genome sequence, and to other independently constructed Eucalyptus linkage maps. CONCLUSIONS: These are the first large scale chromosomal rearrangements discovered between eucalypts. Nonetheless, in the general context of plants, the genomic structure of the two genera was remarkably conserved; adding to a growing body of evidence that conservation of genome structure is common amongst woody angiosperms.

Quantitative trait loci for key defensive compounds affecting herbivory of eucalypts in Australia.

* Formylated phloroglucinols (FPCs) are key defensive compounds that influence herbivory by mammals and arthropods in eucalypts. However, the genetic architecture underlying variation in their levels remains poorly understood. * Quantitative trait loci (QTL) analysis for the concentrations of two major FPCs, sideroxylonal A and macrocarpal G, was conducted using juvenile leaves from 112 clonally duplicated progenies from an outcross F2 of Eucalyptus globulus. * Two unlinked QTL were located for macrocarpal, while another unlinked QTL was located for sideroxylonal. The sideroxylonal QTL collocated with one for total sideroxylonal previously reported using adult Eucalyptus nitens foliage, providing independent validation in a different evolutionary lineage and a different ontogenetic stage. * Given the potential widespread occurrence of these QTL, their ontogenetic stability, and their impact on a range of dependent herbivores, it is possible that they have extended phenotypic effects in the Australian forest landscape.

Abnormalities of motor timing in Huntington's disease.

The ability of patients with Huntington's disease (HD) and control subjects to produce rhythmic finger tapping movements at target frequencies (1-5 Hz) signalled by auditory cues, and to sustain the tapping tempo following sudden withdrawal of cues, was investigated. HD performance, in both the presence and absence of cues, was characterised by, (i) marked irregularity of instantaneous tapping rates and (ii) a tendency to tap too slowly at higher (3-5 Hz) frequency targets and too rapidly at low target frequencies. Analysis of the variability of inter-tap intervals, during uncued tapping at a target rate of 1.8 Hz, using Wing and Kristofferson's model of motor timing (Wing AM, Kristofferson AB. Percept. Psychophys. 1973; 14: 5-12), indicated disturbances of both hypothetical 'clock' and 'motor implementation' systems in HD.

The accuracy and precision of timing of self-paced, repetitive movements in subjects with Parkinson's disease.

In separate experiments, we studied the temporal accuracy and precision of self-paced, repetitive finger-tapping in two groups of 12 patients with Parkinson's disease and a group of 12 controls matched to the patients with respect to age and general cognitive state. One group (I) of patients was studied initially following 12-15 h abstinence from normal levodopa medication ('off') and again, subsequently, approximately 1 h after ingestion of a single normal dose ('on'). A second group (II) of patients, each of whom had bilaterally asymmetrical neurological signs, was tested using 'worse' and 'better' hands separately. Within each session, subjects were tested repeatedly on a tapping task during which they were required to produce a regular series of self-timed inter-tap intervals, the target duration (550 ms) of which had been established previously during an initial period of tapping in synchrony with the beats of a regular metronome. We employed Wing and Kristofferson's (1973) model of control of motor timing to partition the total variance (TV) about the mean inter-response interval (IRI) produced during the self-paced phase of each run into separate components ['clock' variance (CV) and 'motor-delay' variance (MDV)] attributable to hypothetical 'clock' and 'motor-implementation' processes. Although the mean self-paced IRI of parkinsonian patients was generally shorter than that of controls, only during the 'on' medication condition (Group I) was it significantly so. By comparison with control values, and those observed during the 'on' medication condition, values of TV, CV and MDV in Group I were all significantly higher when subjects were 'off' medication. During the 'on' medication condition, only CV was significantly higher than the control value. In Group II, values of TV, CV and MDV associated with use of the 'worse' hand were all significantly higher than both control values and those associated with use of the 'better' hand. Values of these variables when subjects used the 'better' hand did not, however, differ significantly from control values. The theoretical import of these results is discussed in the light of several important procedural, statistical and computational issues and we conclude that TV, CV, and MDV may all vary significantly as a function of the efficacy of dopaminergic transmission in the basal ganglia.

Arguing along the slippery slope of human embryo research.

One frequent argument in the debate over federal funding of human embryo research is the slippery slope argument. Slope arguments can be of several types: either logical, empirical, or full (a combination of logical and empirical slope arguments, with an additional psychological premise). A full slope argument against human embryo research suggests that funding embryo research could undermine current protections for human subjects research, erode respect for persons with disabilities, and encourage eugenics practices. While the Panel commissioned by the National Institutes of Health to issue funding guidelines regarding human embryo research acknowledges some slippery slope concerns, the Panel's final report fails to address such concerns in any depth. Given this failure seriously to address these valid concerns, federal funding of embryo research should not proceed at this time.

The influence of external timing cues upon the rhythm of voluntary movements in Parkinson's disease.

The ability of patients with Parkinson's disease (PD) and healthy subjects to synchronise finger tapping, produced by rhythmic wrist movements, with auditory signals of target frequencies (range 1-5 Hz) and to sustain such rhythms following sudden withdrawal of auditory cues was studied. Healthy subjects were able, in the presence of auditory cues, to duplicate target frequencies accurately over the range investigated both in terms of mean tapping rate and in regularity of tapping. PD patients were less accurate under these conditions and on average tended to tap too rapidly at the lower (1-3 Hz) target frequencies and too slowly at the highest (5 Hz) target frequency. In addition, the variability of their tapping rhythms was generally greater. Healthy subjects were able to sustain tapping rhythms well following suppression of auditory signals. By contrast, withdrawal of external timing cues resulted in marked impairment of the patients' rhythm generation. At lower frequency targets (1-3 Hz) patients' tapping rates increased over rates which were already elevated in the presence of external cues. Conversely, at higher target frequencies (4-5 Hz), the average tapping rate tended to decline further from previously depressed levels. The accuracy of almost all patients fell outside the normal range. Two patterns of tapping errors were found. The first was hastening of tapping which was most evident at intermediate target frequencies. The second was faltering which occurred mainly at the higher target frequencies. These forms of behaviour may result from inherent abnormalities of internal rhythm generation since they occurred both in the presence and absence of external timing signals. Overall, our findings are consistent with the view that the basal ganglia have a role in the internal cueing of repetitive voluntary movements.

Empty sella syndrome associated with partial hypopituitarism (visualized on MRI scan).

The empty sella syndrome has become a rather frequent finding in magnetic resonance imaging (MRI) scanning. The usual presentation of empty sella syndrome involves an incidental finding on a computed tomography scan or an MRI scan. It is unusual to find empty sella syndrome associated with hypopituitarism. The authors describe such an unusual finding in a 54-year-old nulliparous woman.

A new lethal sclerosing bone dysplasia.

A neonate is described with a lethal sclerosing bone dysplasia associated with prenatal fractures and craniofacial abnormalities including microcephaly, exophthalmos, hypoplastic nose and mid-face, small jaw and nodular hyperplasia of the gums. Parental consanguinity suggests that an autosomal recessive mutation is the likely aetiology.

Major surgery in leukemia.

Complications of leukemia that required surgery in twenty-five patients over a five year interval were reviewed. Sixteen patients with chronic leukemia underwent a total of twenty-one operations with one operative death. Nine patients with acute leukemia required ten operations, with two operative deaths. These patients tend to have specific types of complications that are particular to leukemic patients, and with proper support the majority of these patients can be benefited.

Prolonged survival from renal cell carcinoma after renal allotransplantation.

We herein report on a patient who was subjected to bilateral nephrectomy in the course of treating unilateral renal cell carcinoma. The patient has survived for 3 1/2 years free of tumor and has had normal renal function after a 4 antigen match cadaver kidney allograft.