In vitro adventitious root induction in Antirrhinum majus L.

A broadly applicable method for the successful induction of root systems in a number of cultivars of A. majus has been determined. This involves a double filter-paper bridge with a liquid medium for root induction and allows the transfer of culture-grown plantlets to a glasshouse environment with minimal disturbance to the plant as a whole. 100% survival of transferred plantlets has been achieved with the inclusion of a few simple precautions upon shoot transfer and during the initial stages of plant establishment in vivo.     

The lectotype of Sphenobaiera Ikorfatensis (Seward) Florin, a ginkgophyte from the Lower Cretaceous of western Greenland

Use of the genus Sphenobaiera Florin for deeply divided ginkgoalean leaves lacking a petiole is discussed. The type material of the species Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous at Ikorfat in West Greenland is diagnosed, redescribed and the lectotype designated. The cuticle, which is described and figured in detail for the first time, shows the leaf to be amphistomatic and allows previous identifications of Sphenobaiera ikorfatensis in Lower Cretaceous floras from Siberia and China to be confirmed.     

DmsD is required for the biogenesis of DMSO reductase in Escherichia coli but not for the interaction of the DmsA signal peptide with the Tat apparatus

The DmsD protein is essential for the biogenesis of DMSO reductase in Escherichia coli, and binds the signal peptide of the DmsA subunit, a Tat substrate. This suggests a role as a guidance factor to target pre-DmsA to the translocase. Here, we have analysed the export of fusion proteins in which the DmsA and TorA signal peptides are fused to green fluorescent protein. Both chimeras are efficiently exported to the periplasm in wild-type E. coli cells and we show that their export efficiencies are essentially identical in a mutant lacking DmsD. An authentic Tat substrate, TMAO reductase, is also efficiently exported in the dmsD mutant. The data indicate that DmsD carries out a critical role in DMSO reductase biogenesis/assembly but is not required for the functioning of the DmsA signal peptide.     

Entacapone Reduces Cortical Activation in Parkinson's Disease with Wearing-Off: A f-MRI Study

Background and Purpose

Wearing-off is one of the most frequent problems encountered by levodopa-treated patients. Entacapone, a peripheral inhibitor of catechol-O-methyltransferase (COMT), reduces this motor complication by prolonging the effect of levodopa. We sought to understand the impact of COMT-inhibition on movement execution in PD patients with wearing-off by comparing functional magnetic resonance imaging (f-MRI) activation patterns prior to and during entacapone treatment. Our hypothesis was to determine whether changes in cortical activation are associated to COMT-inhibitor treatment.

Methods

Nine levodopa-treated non-demented PD patients with wearing-off were prospectively studied in two f-MRI session, prior to and during entacapone treatment. A group of control subjects were also studied for comparison.

Results

The patients significantly improved under COMT-inhibitor treatment based on home diaries. F-MRI results showed that at baseline the patients presented a bilateral activation of the primary motor, controlateral premotor cortex and supplementary motor area, as well as ipsilateral cerebellum. During treatment with entacapone, PD patients showed reductions in the activations of these cortical areas and a decreased activation in the ipsilateral cerebellum.

Conclusions

Our preliminary findings indicate that f-MRI is able to detect cortical activation changes during long-term modulation of dopaminergic treatment in PD patients with wearing-off, and thus, this technique could be further investigated in advanced PD patients.     

Life history constraints explain negative relationship between fish productivity and dissolved organic carbon in lakes

Resource availability constrains the life history strategies available to organisms and may thereby limit population growth rates and productivity. We used this conceptual framework to explore the mechanisms driving recently reported negative relationships between fish productivity and dissolved organic carbon (DOC) concentrations in lakes. We studied populations of bluegill (Lepomis macrochirus) in a set of lakes with DOC concentrations ranging from 3 to 24 mg/L; previous work has demonstrated that primary and secondary productivity of food webs is negatively related to DOC concentration across this gradient. For each population, we quantified individual growth rate, age at maturity, age‐specific fecundity, maximum age, length‐weight and length‐egg size relationships, and other life history characteristics. We observed a strong negative relationship between maximum size and DOC concentration; for instance, fish reached masses of 150 to 260 g in low‐DOC lakes but <120 g in high‐DOC lakes. Relationships between fecundity and length, and between egg size and length, were constant across the DOC gradient. Because fish in high‐DOC lakes reached smaller sizes but had similar fecundity and egg size at a given size, their total lifetime fecundity was as much as two orders of magnitude lower than fish in low‐DOC lakes. High DOC concentrations appeared to constrain the range of bluegill life history strategies available; populations in high‐DOC lakes always had low initial growth rates and high ages at maturity, whereas populations in low‐DOC showed higher variability in these traits. This was also the case for the intrinsic rates of natural increase of these populations, which were always low at the high end of the DOC gradient. The potentially lower capacity for fish populations in high‐DOC lakes to recover from exploitation has clear implications for the sustainable management of recreational fisheries in the face of considerable spatial heterogeneity and ongoing temporal change in lake DOC concentrations.     

Predicting diatom communities at the genus level for the rapid biological assessment of rivers

1. Diatoms were sampled in the spring of 1994 and the autumn of 1995 at 137 pristine or near-pristine reference sites on large and small streams at various altitudes in eastern New South Wales and Victoria. Scrapings were taken from five firm substrata across a range of microhabitat conditions at each site on each occasion. For each substratum, 100 valves were identified to genus level. 2. Multivariate statistical models were constructed to predict the probability of occurrence of each genus at a given site under near-pristine conditions on the basis of physical features of the site that are not affected by human activity. Model predictions were compared with the flora observed at the reference sites and at 55 test sites affected by varying degrees of human disturbance. 3. Test sites were characterized more by the presence of genera not predicted by the model than by the absence of predicted genera. The degree of departure from model predictions was related mainly to increasing alkalinity, electrical conductivity, hardness and pH of river water. We therefore conclude that the main effect of human activity on the composition of diatom communities in the rivers of coastal south-eastern Australia has been to increase genus richness through enrichment with alkaline salts. 4. The models did not perform as well as similar models applied to river macroinvertebrates at the family level, perhaps because of greater temporal variability in diatom communities and differences in the environmental variables to which diatoms and macroinvertebrates respond. Means of improving the current models are discussed.     

Association between reduced bronchodilatory effect of deep inspiration and loss of alveolar attachments

Background

We have previously shown that the bronchodilatory effect of deep inspiration is attenuated in individuals with COPD. This study was designed to investigate whether the impairment in this effect is associated with loss of alveolar attachments.

Methods

We measured deep inspiration (DI)-induced bronchodilation in 15 individuals with and without COPD (67 ± 2.2 yrs of age, mean ± SEM) undergoing lobar resection for peripheral pulmonary nodule. Prior to surgery, we measured TLCO and determined the bronchodilatory effect of deep inspiration after constricting the airways with methacholine. The number of destroyed alveolar attachments, as well as airway wall area and airway smooth muscle area, were determined in tumor-free, peripheral lung tissue.

Results

The bronchodilatory effect of deep inspiration correlated inversely with the % destroyed attachments (r = -0.51, p = 0.05) and directly with the airway smooth muscle area (r = 0.59, p = 0.03), but not with the total wall area (r = 0.39, p = 0.15).

Conclusion

We postulate that attenuation of airway stretch due to loss of alveolar attachments contributes to the loss of the bronchodilatory effect of lung inflation in COPD.