Measuring Success: Evaluating the Restoration of a Grassy Eucalypt Woodland on the Cumberland Plain, Sydney, Australia

Abstract We compared the floristic composition and structure of restoration areas of eucalypt woodland with untreated pasture (control) and remnant vegetation (reference) in western Sydney. The restored areas comprised over 1,000 ha of abandoned pasture, which had been treated to reduce weeds and planted with seedlings of 26 native plant species raised from seed obtained locally from remnant vegetation. Plantings were carried out 0–9 years ago. Floristic composition was measured in quadrats using frequency scores and cover abundance. As far as possible treatments and restoration ages were replicated across sites. Ordination and analyses of similarity failed to distinguish the composition of restored vegetation from that of untreated pasture, which were both significantly different from that of remnant vegetation. There was a weak compositional trend with age of restored vegetation, but this was not in the direction of increasing resemblance to remnant vegetation. There was some evidence for convergence in structural features of restored with remnant vegetation, but this was at least partly attributed to plant growth. Subject to constraints imposed by the sampling design, environmental factors, and spatial variation were discounted as explanations for the results. The results therefore suggest either failure of restoration treatments or a restoration trajectory that is too slow to detect within 10 years of establishment. Our conclusions agree with those of similar studies in other ecosystems and support: (1) the need to monitor restoration projects against ecological criteria with rigorous sampling designs and analytical methods, (2) further development of restoration methods, and (3) regulatory approaches that seek to prevent damage to ecosystems rather than those predicated on replacing losses with reconstructed ecosystems.     

Effects of anti-inflammatory drugs on fever and neutrophilia induced by Clostridium difficile toxin B

This study investigated the ability of Clostridium difficile toxin B, isolated from the VPI 10463 strain, to induce fever and neutrophilia in rats. Intravenous injection of toxin B (0.005-0.5 mug/kg) evoked a dose-dependent increase in body temperature. The febrile response to 0.5 mug/kg of the toxin started in 2.5 h, peaked at 5 h, and subsided fully within 24 h. Toxin B also induced a dosedependent neutrophilia. Pretreatment with indomethacin (2 mg/kg, i.p.) did not affect the neutrophilia induced by toxin B, but significantly reduced the febrile response measured 4 to 8 h after toxin B injection. Dexamethasone (0.5 mg/ kg) also markedly diminished the febrile response induced by toxin B. These results show that Clostridium difficile toxin B induced a febrile response susceptible to inhibition by dexamethasone and indomethacin. Furthermore, they suggest that prostaglandins are not involved in the neutrophilia caused by this toxin.     

The role of temperature in the regulation of the circadian rhythm of CO2 fixation in Bryophyllum fedtschenkoi

Detached leaves of Bryophyllum fedtschenkoi Hamet et Perrier kept in normal air show a single period of net CO₂ fixation on transfer to constant darkness at temperatures in the range 0–25 °C. The duration of this initial fixation period is largely independent of temperature in the range 5–20 °C, but lengthens very markedly at temperatures below 4 °C, and is reduced at temperatures above 25 °C. The onset of net fixation of CO₂ on transfer of leaves to constant darkness is immediate at low temperatures, but is delayed as the temperature is increased. The ambient temperature also determines whether or not a circadian rhythm of CO₂ exchange occurs. The rhythm begins to appear at about 20 °C, is most evident at 30 °C and becomes less distinct at 35 °C. The occurrence of a distinct circadian rhythm in CO₂ output at 30° C in the absence of a detectable rhythm in PEPCase kinase activity shows that the kinase rhythm is not a mandatory requirement for the rhythm of PEPCase activity. However, when it occurs, the kinase rhythm undoubtedly amplifies the PEPCase rhythm.Abbreviation PEPCase phosphoenolpyruvate carboxylase We thank the Agricultural and Food Research Council for financial support for this work.     

Photosynthetic acclimation to elevated CO2 in poplar grown in glasshouse cabinets or in open top chambers depends on duration of exposure

The effects of elevated CO₂ were studied on the photosyntheticgas exchange behaviour and leaf physiology of two contrastingpoplar (Populus) hybrids grown and treated in open top chambers(OTCs in Antwerp, Belgium) and in closed glasshouse cabinets(GHCs in Sussex, UK). The CO₂ concentrations used in the OTCswere ambient and ambient +350 µmol mol^–1 while inthe GHCs they were c. 360 µmol mol^–1 versus 719µmol mol^–1. Measurements of photosynthetic gas exchangewere made for euramerican and interamerican poplar hybrids incombination with measurements of dark respiration rate and Rubiscoactivity. Significant differences in the leaf anatomy and structure(leaf mass per area and chlorophyll content) were observed betweenthe leaves grown in the OTCs and those grown in the GHCs. ElevatedCO₂ stimulated net photosynthesis in the poplar hybrids after1 month in the GHCs and after 4 months in the OTCs, and therewas no evidence of downward acclimation (or down-regulation)of photosynthesis when the plants in the two treatments weremeasured in their growth CO₂ concentration. There was also noevidence of down-regulation of Rubisco activity and there wereeven examples of increases in Rubisco activity. Rubisco exerteda strong control over the light-saturated rate of photosynthesis,which was demonstrated by the close agreement between observednet photosynthetic rates and those that were predicted fromRubisco activities and Michaelis-Menten kinetics. After 17 monthsin elevated CO₂ in the OTCs there was a significant loss ofRubisco activity for one of the hybrid clones, i.e. Beaupr,but not for clone Robusta. The effect of the CO₂ measurementconcentration (i.e. the short-term treatment effect) on netphotosynthesis was always larger than the effect of the growthconcentration in both the OTCs or GHCs (i.e. the longterm growthCO₂ effect), with one exception. For the interamerican hybridBeaupr dark respiration rates in the OTCs were not significantlyaffected by the elevated CO₂ concentrations. The results suggestthat for rapidly growing tree species, such as poplars, thereis little evidence for downward acclimation of photosynthesiswhen plants are exposed to elevated CO₂ for up to 4 months;longer term exposure reveals loss of Rubisco activity. Key words: Elevated CO₂, Populus, Rubisco, photosynthesis, chlorophyll content     

Non-protein-bound iron within bacterial cells and the action of bleomycin

Damage to DNA by bleomycin in vitro is entirely dependent on the presence of an iron salt and molecular oxygen. This same reaction has been used to measure non-protein-bound iron in different bacterial species. Although several of the species examined were insensitive to the toxic effects of bleomycin, they all contained a concentration of non-protein-bound iron which should have been sufficient to allow iron-dependent damage to DNA. Other factors such as permeability or inactivation of the drug must explain their apparent insensitivity.     

Transparent Plastic Incubator for the Anaerobic Glove Box

An incubator designed for use inside an anaerobic glove box is described. The incubator is made of transparent plastic material, has sliding plastic doors, and can be made in various sizes from readily available materials.     

The reduction of methemerythrin by e-aq and CO2- from pulse radiolysis studies.

The rate constants for reduction of methemerythrin from Phascolopsis gouldii and Themiste pyroides by hydrated electrons are 2.0 and 3.9 x 10(9) M(-1)s(-1), respectively, at pH 8.2, I = 0.03 M, and 25 degrees C. There is only a small increase in rate when the pH is lowered to 6.3 and a very small decrease when the ionic strength is raised to 0.1 M. Adding azide ion (to form the met-azide adduct) has little effect on the reactivity towards e-aq. For the monomer form, metmyohemerythrin from T. pyroides, the reaction rate constant is 4.5 x 10(9) M(-1)s(-1). Methemerythrin from T. pyroides reacts with CO2- with a rate constant 6.8 x 10(7) M(-1)s(-1). The reactivity sequence e-aq greater than CO2- greater than SO2- (from dithionite reduction) towards methemerythrin is the same as that observed with reduction of heme proteins but the rate constants are some 10 to 100 times smaller for the former. Only 10 to 20% of the e-aq or CO2- radicals generated effect reduction of the iron centers in methemerythrin.     

Mutagens in the feces of 3 South-African populations at different levels of risk for colon cancer.

The incidence of mutagens in the feces of 3 South-African populations at different risk levels for colon cancer has been determined. Lyophilized fecal samples were extracted with ether and the mutagenicity of the extracts determined using the Salmonella/mammalian microsome mutagenicity test. 19% of the samples from urban white South-Africans, a population at a high risk for colon cancer, were mutagenic using Salmonella typhimurium strain TA100. This incidence was significantly greater (p less than 0.001) than the incidence of mutagen excretion in the low-risk populations of urban blacks (2%) and rural blacks (0%). This pattern was also obtained using Salmonella typhimurium strain TA98. The incidence of mutagen excretion for urban whites was 10%, as compared to 5% and 2% for urban and rural blacks, respectively.     

Durvilldiol and durvillonol: Structure and occurrence

The triterpenoids durvilldiol and durvillonol, isolated in earlier studies from the lichen Pseudocyphellaria berberina, syn. P. durvillei, are identified as stictane-3β,22α-diol and 22α-hydroxystictan-3-one respectively.     

Transport of 5-hydroxytryptamine by dense granules from porcine platelets

A method is described for the isolation of a homogeneous preparation of dense granules from procine platelets. The purified dense granule fraction contained approximately 400 nmol of 5-hydroxytryptamine/mg of protein and appeared to be homogeneous when examined by electron microscopy. Isolated dense granules transport exogenously added 5-hydroxytryptamine via two mechanisms: 1) a carrier-mediated process predominating at low substrate concentrations and 2) a diffusion-controlled process predominating at high substrate concentrations. Temperature studies revealed an apparent energy of activation of 14.9 kcal/mol for the carrier-mediated transport. Kinetic data yielded a Km of 3.3 micron and a Vmax of 0.79 nmol/min/mg of protein for the mediated transport process. Steady state uptake was sensitive to changes in medium osmotic pressure and a decline in uptake below 300 mosM was correlated with release of endogenous 5-hydroxytryptamine. The transport was inhibited by a number of structural analogs of 5-hydroxytryptamine. These results demonstrate the existence of a carrier-mediated transport system for 5-hydroxytryptamine in the membranes of the platelet dense granules.