Kinetics of baculovirus replication and release using real-time quantitative polymerase chain reaction

The study of viral-based processes is hampered by (a) their complex, transient nature, (b) the instability of products, and (c) the lack of accurate diagnostic assays. Here, we describe the use of real-time quantitative polymerase chain reaction to characterize baculoviral infection. Baculovirus DNA content doubles every 1.7 h from 6 h post-infection until replication is halted at the onset of budding. No dynamic equilibrium exists between replication and release, and the kinetics are independent of the cell density at the time of infection. No more than 16% of the intracellular virus copies bud from the cell. (C) 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 476-480, 2002; DOI 10.1002/bit.10126.

Fatal monensin toxicity in a dog after chewing a bovine intra-ruminal slow-release device

A 20kg, 10-month-old male Kelpie developed a rapid onset of profound paresis progressing to flaccid paralysis and dyspnoea, followed by death about 36 hours after chewing on a partly discharged anti-bloat capsule from a dead cow. Intoxication by monensin in the capsule was considered the cause of death. No Lodes holocyclus were found on the dog. Evidence of muscle damage was seen in clinical biochemistry assays of plasma, but consent for necropsy was not obtained. The median lethal dose for Beagle dogs of the material contained in anti-bloat capsules is 0.5-1.0g. As this represents a serious toxicity risk if dogs chew these devises, the manufacturer includes a warning on potential dog toxicity in product literature.

Zeolite/rock phosphate - a novel slow release phosphorus fertiliser for potted plant production

A glasshouse study was undertaken to determine if the zeolite mineral clinoptilolite from an Australian deposit in combination with rock phosphate (RP) could significantly enhance the uptake of P by sunflowers. The zeolite/RP combination was intended to act as an exchange-fertiliser, with Ca2+ exchanging onto the zeolite in response to plant uptake of nutrient cations (NH4+ or K) enhancing the dissolution of the RP. A reactive RP (Sechura) and a relatively non-reactive RP (Duchess) were examined. Zeolite was used in Ca2+-, K+- and NH4+-saturated forms at ratios of 3.5:1 and 7:1 with RP; Ca2+-zeolite was considered the control, with exchange-induced dissolution possible from K+-and NH4+-zeolite, The zeolite/RP mixture was applied as a vertical band adjacent to the sunflower seedling. In addition, N was supplied as urea in an effort to determine if RP dissolution resulted from H+ release by nitrification. Phosphorus supply from the zeolite/RP system was compared with an available P source (KH2PO4). The experiment clearly demonstrated greatly enhanced plant uptake of P from RP when applied in combination with NH4-zeolite, though the P uptake was lower than that from the soluble P source. The zeolite/RP interaction was much more effective with the reactive R-P than the non-reactive material, Within the NH4+-zeolite/RP band, root proliferation was greatly increased, as would be expected in an exchange-fertiliser system. The K+-zeolite system did not produce a significantly greater yield than the Ca2+-zeolite control, probably because adequate K+ supply from the basal application reduced uptake within the zeolite/RP band, thus reducing the extent of exchange-induced dissolution. Nevertheless, increased root proliferation within the band was observed, implying that exchange-induced dissolution may also be possible from this system. The zeolite/RP system offers the considerable advantage of P release in response to plant demand and is unique in this regard. (C) 2002 Elsevier Science B.V. All rights reserved.

Behavior of argon gas release from manganese oxide minerals as revealed by Ar-40/Ar-39 laser incremental heating analysis

Manganese oxides in association with paleo-weathering may provide significant insights into the multiple factors affecting the formation and evolution of weathering profiles, such as temperature, precipitation, and biodiversity. Laser probe step-heating analysis of supergene hollandite and cryptomelane samples collected from central Queensland, Australia, yield well-defined plateaus and consistent isochron ages, confirming the feasibility, dating very-fined supergene manganese oxides by Ar-40/(39) Ar technique. Two distinct structural sites hosting Ar isotopes can be identified in light of their degassing behaviors obtained by incremental heating analyses. The first site, releasing its gas fraction at the laser power 0.2-0.4 W, yields primarily Ar-40(atm), Ar-38(atm), and Ar-36(atm), (atmospheric Ar isotopes). The second sites yield predominantly Ar-40* (radiogenic Ar-40), Ar-39(K), and Ar-38(K) (nucleogenic components), at similar to0.5-1.0 W. There is no significant Ar gas released at the laser power higher than 1.0 W, indicating the breakdown of the tunnel sites hosting the radiogenic and nucleogenic components. The excellent match between the degassing behaviors of Ar-40*, Ar-39(K), and Ar-38(K) suggests that these isotopes occupy the same crystallographic sites and that Ar-39(K) loss from the tunnel site by recoil during neutron irradiation and/or bake-out procedure preceding isotopic analysis does not occur. Present investigation supports that neither the overwhelming atmospheric Ar-40 nor the very-fined nature of the supergene manganese oxides poses problems in extracting meaningful weathering geo-chronological information by analyzing supergene manganese oxides minerals.

Sustained high levels of foliar herbivory of the mangrove Rhizophora stylosa by a moth larva Doratifera stenosa (Limacodidae) in north-eastern Australia

The moth larva, Doratifera stenosa (Lepidoptera: Limacodidae), was observed feeding voraciously in great numbers on mature leaves of Rhizophora stylosa in mangroves at Port Curtis in Central Queensland, NE Australia. This behaviour was considered unusual since mangroves, and the Rhizophora species in particular, reportedly harbour few herbivores and have relatively low levels of herbivory, less than 10%. During a two year period (1996-1998), larvae were observed consuming around 30-40% of leaves in the canopy each year, and the mangroves appeared able to sustain these high levels of herbivory. The impact on trees was assessed in conjunction with a study of the herbivore, its behaviour and life history, in an attempt to explain the occurrence. Larvae were 1-2 cm in length, bright green and gregarious, with numerous small, stinging hairs along their upper bodies. Feeding was in small cohort groups of 5-70 individuals that broke up immediately prior to each moult after which they regrouped in much larger numbers of mixed cohorts to form single-file processions across branches, stems and prop roots. In this way, they moved to neighbouring trees with less affected foliage. One of the outstanding characteristics of this herbivore was its ability to desist from killing host trees although it appeared quite capable of doing so had it remained on individual trees. By moving from tree to tree, the herbivore was able to heavily crop Rhizophora foliage in an apparently sustainable manner. These findings demonstrate the role and importance of foliar herbivory in severely affected forests and how such instances best not be ignored or treated as curiosities in future assessments of herbivory and forest turnover in mangrove ecosystems.

Limb constriction as a complication of intra-uterine vesico-amniotic shunt: Fetoscopic release

Complete fetal bladder outlet obstruction was first diagnosed in a fetus at 13.5 weeks. After sequential vesico-centesis had shown good renal function, a vesico-amniotic shunt was inserted at 17 weeks with a Rodeck catheter. The procedure was successful and amniotic fluid volume re-accumulated to normal levels. A detailed scan at 20 weeks showed that the distal free end of the catheter was wound round the left fetal thigh. As the fetus grew, there was progressive constriction of the fetal thigh by the catheter. By 29 weeks, Doppler blood flow changes to the left leg were apparent. Fetoscopic surgery was performed at 30 weeks to release the constriction. The catheter was divided successfully, but the divided end of the shunt subsequently retracted into the fetal abdomen, producing urinary ascites, bilateral hydroureter and hydronephrosis. The baby was delivered at 31.5 weeks in good condition. Endoscopic resection of anterior and posterior urethral valves was performed at 6 months of age. At 2 years, the child has normal renal function, growth parameters and developmental milestones. Mild indentation of the left thigh was still apparent, although there was no functional impairment. Copyright (C) 2002 S. Karger AG, Basel.

Load-unload response ratio and accelerating moment/energy release critical region scaling and earthquake prediction

The main idea of the Load-Unload Response Ratio (LURR) is that when a system is stable, its response to loading corresponds to its response to unloading, whereas when the system is approaching an unstable state, the response to loading and unloading becomes quite different. High LURR values and observations of Accelerating Moment/Energy Release (AMR/AER) prior to large earthquakes have led different research groups to suggest intermediate-term earthquake prediction is possible and imply that the LURR and AMR/AER observations may have a similar physical origin. To study this possibility, we conducted a retrospective examination of several Australian and Chinese earthquakes with magnitudes ranging from 5.0 to 7.9, including Australia's deadly Newcastle earthquake and the devastating Tangshan earthquake. Both LURR values and best-fit power-law time-to-failure functions were computed using data within a range of distances from the epicenter. Like the best-fit power-law fits in AMR/AER, the LURR value was optimal using data within a certain epicentral distance implying a critical region for LURR. Furthermore, LURR critical region size scales with mainshock magnitude and is similar to the AMR/AER critical region size. These results suggest a common physical origin for both the AMR/AER and LURR observations. Further research may provide clues that yield an understanding of this mechanism and help lead to a solid foundation for intermediate-term earthquake prediction.

NPS-2143 - Treatment of osteoporosis - Calcilytic

Efforts to discover new treatments for osteoporosis led to the identification of the potent and selective, small-molecule calcium receptor antagonist NPS-2143. NPS-2143 is the prototype calcilytic drug, designed to act on calcium receptors on the surface of parathyroid glands, stimulating the release of the body's own stores of native parathyroid hormone (PTH). In osteopenic ovariectomized rats, daily oral administration of NPS-2143 resulted in moderate but sustained increases in plasma PTH levels and marked increases in bone formation and resorption, with no net bone gain or loss. The combination of NPS-2143 and estrogen increases bone formation and density to a greater extent than either agent alone. These results suggest that NPS-2143 may be useful in the treatment of established osteoporosis.

No evidence for inhibition of ENaC through CFTR-mediated release of ATP

Both purinergic stimulation and activation of cystic fibrosis transmembrane conductance regulator (CFTR) increases Cl- secretion and inhibit amiloride-sensitive Na+ transport. CFTR has been suggested to conduct adenosine 5'-triphosphate (ATP) or to control ATP release to the luminal side of epithelial tissues. Therefore, a possible mechanism on how CFTR controls the activity of epithelial Na+ channels (ENaC) could be by release of ATP or uridine 5'-triphosphate (UTP), which would then bind to P2Y receptors and inhibit ENaC. We examined this question in native tissues from airways and colon and in Xenopus oocytes. Inhibition of amiloride-sensitive transport by both CFTR and extracellular nucleotides was observed in colon and trachea. However, nucleotides did not inhibit ENaC in Xenopus oocytes, even after coexpression of P2Y(2) receptors. Using different tools such as hexokinase, the P2Y inhibitor suramin or the Cl- channel blocker 4,4'diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), we did not detect any role of a putative ATP secretion in activation of Cl- transport or inhibition of amiloride sensitive short circuit currents by CFTR. In addition, N-2,2'-O-dibutyrylguanosine 3',5-cyclic monophosphate (cGMP) and protein kinase G (PKG)-dependent phosphorylation or the nucleoside diphosphate kinase (NDPK) do not seem to play a role for the inhibition of ENaC by CFTR, which, however, requires the presence of extracellular Cl-. (C) 2002 Elsevier Science B.V. All rights reserved.

Spatial and temporal changes in multiple hormone groups during lateral bud release shortly following apex decapitation of chickpea (Cicer arietinum) seedlings

Although the co-ordination of promotive root-sourced cytokinin (CK) and inhibitory shoot apex-sourced auxin (IAA) is central to all current models on lateral bud dormancy release, control by those hormones alone has appeared inadequate in many studies. Thus it was hypothesized that the IAA : CK model is the central control but that it must be considered within the relevant timeframe leading to lateral bud release and against a backdrop of interactions with other hormone groups. Therefore, IAA and a wide survey of cytokinins (CKs), were examined along with abscisic acid (ABA) and polyamines (PAs) in released buds, tissue surrounding buds and xylem sap at 1 and 4 h after apex removal, when lateral buds of chickpea are known to break dormancy. Three potential lateral bud growth inhibitors, IAA, ABA and cis-zeatin 9-riboside (ZR), declined sharply in the released buds and xylem following decapitation. This is in contrast to potential dormancy breaking CKs like trans-ZR and trans-zeantin 9-riboside 5'phosphate (ZRMP), which represented the strongest correlative changes by increasing 3.5-fold in xylem sap and 22-fold in buds. PAs had not changed significantly in buds or other tissues after 4 h, so they were not directly involved in the breaking of bud dormancy. Results from the xylem and surrounding tissues indicated that bud CK increases resulted from a combination synthesis in the bud and selective loading of CK nucleotides into the xylem from the root.

Transport and metabolism of xylem cytokinins during lateral bud release in decapitated chickpea (Cicer arietinum) seedlings

Although cytokinins (CKs) are widely thought to have a role in promoting shoot branching, there is little data supporting a causative or even a correlative relationship between endogenous CKs and timing of bud outgrowth. We previously showed that lateral bud CK content increased rapidly following shoot decapitation. However, it is not known whether roots are the source of this CK. Here, we have used shoot decapitation to instantaneously induce lateral bud release in chickpea seedlings. This treatment rapidly alters rate and direction of solvent and solute (including CK) trafficking, which may be a passive signalling mechanism central to initiation of lateral bud release. To evaluate changes in xylem transport, intact and decapitated plants were infiltrated with [H-3]zeatin riboside ([H-3]ZR), a water-soluble blue dye or [H-3]H2O by injection into the hypocotyl. All three tracers were recovered in virtually all parts of the shoot within I h of injection. In intact plants, solute accumulation in the lateral bud at node 1 was significantly less than in the adjacent stipule and nodal tissue. In decapitated plants, accumulation of [H-3]ZR and of blue dye in the same bud position was increased 3- to 10-fold relative to intact plants, whereas content of [H-3]H2O was greatly reduced indicating an increased solvent throughput. The stipule and cut stem, predicted to have high evapotranspiration rates, also showed increased solute content accompanied by enhanced depletion of [H-3]H2O. To assess whether metabolism modifies quantities of active CK reaching the buds, we followed the metabolic fate of [H-3]ZR injected at physiological concentrations. Within 1 h, 80-95% of [H-3]ZR was converted to other active CKs (mainly zeatin riboside-5'phosphate (ZRMP) and zeatin (Z)), other significant, but unconfirmed metabolites some of which may be active (O-acetylZR, O-acetylZRMP and a compound correlated with sites of high CK-concentrations) and inactive catabolites (adenosine, adenine, 5'AMP and water). Despite rapid metabolic degradation, the total active label, which was indicative of CK concentration in buds, increased rapidly following decapitation. It can be inferred that xylem sap CKs represent one source of active CKs appearing in lateral buds after shoot decapitation.

What happens after the swallow? Introducing the glottal release sound

Cervical auscultation presents as a noninvasive screening assessment of swallowing. Until now the focus of acoustic research in swallowing has been the characterization of swallowing sounds,. However, it may be that the technique is also suitable for the detection of respiratory sounds post swallow. A healthy relationship between swallowing and respiration is widely accepted as pivotal to safe swallowing. Previous investigators have shown that the expiratory phase of respiration commonly occurs prior to and after swallowing. That the larynx is valved shut during swallowing is also accepted. Previous research indicates that the larynx releases valved air immediately post swallow in healthy individuals. The current investigation sought to explore acoustic evidence of a release of subglottic air post swallow in nondysphagic individuals using a noninvasive medium. Fifty-nine healthy individuals spanning the ages of 18 to 60+ years swallowed 5 and 10 milliliters (ml) of thin and thick liquid boluses. Objective acoustic analysis was used to verify presence of the sound and to characterize its morphological features. The sound, dubbed the glottal release sound, was found to consistently occur in close proximity following the swallowing sound. The results indicated that the sound has distinct morphological features and that these change depending on the volume and viscosity of the bolus swallowed. Further research will be required to translate this information to a clinical tool.

Sustained swimming performance in crocodiles (Crocodylus porosus): Effects of body size and temperature

We examined effects of body size and temperature on swimming performance in juvenile estuarine crocodiles, Crocodylus porosus, over the size range of 30-110 cm total body length. Swimming performance, expressed as maximum sustainable swimming speed, was measured in a temperature- and flow-controlled swimming flume. Absolute sustainable swimming speed increased with body length, but length-specific swimming performance decreased as body length increased. Sustained swimming speed increased with temperature between 15degreesC and 23degreesC, remained constant between 23degrees and 33degreesC, and decreased as temperature rose above 33degreesC. Q(10)-values of swimming speed were 2.60 (+/- 0.091 SE) between 18degreesC and 23degreesC, and there were no differences in Q(10) between crocodiles of different sizes. The broad plateau of thermal independence in swimming speed observed in C. porosus may be of adaptive significance by allowing dispersal of juvenile animals at suboptimal body temperatures.