Pseudoxanthomonas bacteria that drive deposit formation of wood extractives can be flocculated by cationic polyelectrolytes

Runnability problems caused by suspended bacteria in water using industries, have, in contrast to biofilms, received little attention. We describe here that Pseudoxanthomonas taiwanensis, a wide-spread and abundant bacterium in paper machine water circuits, aggregated dispersions of wood extractives ("pitch") and resin acid, under conditions prevailing in machine water circuits (10⁹ cfu ml⁻¹, pH 8, 45°C). The aggregates were large enough (up to 50 μm) so that they could be expected to clog wires and felts and to reduce dewatering of the fiber web. The Pseudoxanthomonas bacteria were negatively charged over a pH range of 3.2–10. Cationic polyelectrolytes of the types used as retention aids or fixatives to flocculate "anionic trash" in paper machines were effective in flocculating the Pseudoxanthomonas bacteria. The polyelectrolyte most effective for this purpose was of high molecular weight (7–8 × 10⁶ g mol⁻¹) and low charge density (1 meq g⁻¹), whereas polyelectrolytes that effectively zeroed the electrophoretic mobility (i.e., neutralized the negative charge) of the bacterium were less effective in flocculating the bacteria. Based on the results, we concluded that the polyelectrolytes functioning by bridging mechanism, rather than by neutralization of the negative charge, may be useful as tools for reducing harmful deposits resulting from interaction of bacteria with wood extractives in warm water industry.     

Ecophysiology of Species with Distinct Leaf Morphologies: Effects of Plastic and Shadecloth Tree Guards

Ecological restoration using seedling tubestock is challenging under a Mediterranean-type climate of hot, dry summers. We investigated the ecophysiological effects of plastic tree guards and shadecloth tree guards during seedling establishment of four co-occurring tree species that differ in leaf morphology. Average temperature was 6.7°C higher in plastic guards than controls over a summer, with a maximum of 53.5°C compared to 47.9°C in controls. Light levels were 2-fold lower in both tree guard treatments relative to control. In spring, photosynthesis and specific leaf area were significantly elevated in shadecloth tree guards relative to other treatments. In summer, photosynthetic rate was significantly lower, and midday photochemical efficiency was significantly higher, in both tree guard treatments relative to controls. The effect of elevated temperature in plastic tree guards may partially explain our results of higher mortality of seedling in plastic tree guards. The relatively elevated spring photosynthesis of seedlings in shadecloth tree guards may partially explain the result of reduced mortality and increased growth in this treatment. We conclude that shadecloth tree guards create a microclimate more favorable for seedling establishment in a Mediterranean-type environment than plastic tree guards and control treatments. Our results may have wide applicability to the range of restoration settings where seedling tubestock is planted, except in environments where low temperature is limiting to plant growth.     

Parental investment in monogamous pairs of Wood Warblers (Phylloscopus sibilatrix)

In Wood WarblersPhylloscopus sibilatrix in South-Central Sweden, paired males spend considerable time trying to attract additional females either in outlying parts of their territory or in a secondary territory at some distance from the first. Approximately 20 % of the paired males succeed in attracting an additional female, while the rest stay monogamous. When the eggs hatch males assist in feeding the young. We studied parental care in monogamous pairs and investigated the proportion of males being paired in relation to the hatching of broods. Both feeding frequency and load size increased with age of the young. Feeding frequencies were higher in males than in females, while there was no difference in load size between the sexes. Nestlings are unable to thermoregulate the first days after hatching, and females spent considerable time brooding them. We also show that males do not gain by deserting the family when the broods hatch, since the probability to attract additional females at that time is low.

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Zusammenfassung In einer Population Südschwedens wendeten die Männchen des Waldlaubsängers erhebliche Zeit auf, um entweder in entfernten Teilen ihres Reviers oder in einem zweiten Revier in einiger Entfernung weitere Weibchen anzulocken. Etwa 20 % der Männchen konnte so ein zweites Weibchen an sich binden, die übrigen blieben monogam. Nach dem Schlüpfen halfen die Männchen bei der Jungenfütterung. Die Brutpflege bei monogamen Paaren wurde untersucht, ebenso das Verhältnis der verpaarten Männchen zu geschlüpften Bruten. Fütterfrequenz und Größe einer Futterportion nahmen mit dem Wachstum der Jungen zu. Bei den Männchen war die Fütterfrequenz höher als bei den Weibchen, nicht jedoch die Größe einer Futterportion. Da die Nestlinge während der ersten Tage ihre Körpertemperatur nicht aufrecht erhalten können, werden sie vom Weibchen ausdauernd gehudert. Männchen gewinnen nichts, wenn sie die Familie nach dem Schlüpfen der Jungen verlassen, da die Wahrscheinlichkeit, ein neues Weibchen zu finden, in dieser Zeit gering ist.

     

The development and purification of a bispecific antibody for lymphokine-activated killer cell targeting against the rat colon carcinoma CC531

In vivo targeting of lymphokine-activated killer (LAK) cells to tumour deposits by bispecific monoclonal antibodies (bimAb) may be a way to improve adoptive immunotherapy. We developed a bimAb against adherent LAK (ALAK) cells and colon tumour CC531 in Wag rats. The bimAb was produced by somatic hybridization of two mouse hybridomas, one producing monoclonal antibodies (mAb) against CD8 (IgG2b, OX8), and the other producing mAb against a CC531-associated antigen (IgG1, CC52). A bimAb-producing clone was selected by an enzyme-linked immunosorbent assay with CC531 tumour cells. BimAb were purified from ascitic fluid by protein A affinity chromatography. Each of five pooled peak fractions was analysed by flow cytometry for the presence of bimAb. Most bimAb were found in a fraction that was eluted at pH 4.5 from protein A. FPLC analysis of this fraction revealed that no parental antibodies were present. The OX8 × CC52 bimAb greatly increased conjugate formation in vitro between ALAK cells and CC531. Results of⁵¹Cr-release assays with CC531 as target cells and ALAK cells as effector cells were not significantly different in the presence or in the absence of the bimAb. The methods we used here, a cell enzyme-linked immunosorbent assay and flow cytometry, are simple methods for development and purification of a bimAb when a functional selection method is not a priori available. The OX8 × CC52 bimAb we developed this way may increase in vivo tumour targeting of ALAK cells and thus augment antitumour effect in vivo.     

Impacts of recent climate change on terrestrial flora and fauna: Some emerging Australian examples

The effects of anthropogenic climate change on biodiversity are well known for some high‐profile Australian marine systems, including coral bleaching and kelp forest devastation. Less well‐published are the impacts of climate change being observed in terrestrial ecosystems, although ecological models have predicted substantial changes are likely. Detecting and attributing terrestrial changes to anthropogenic factors is difficult due to the ecological importance of extreme conditions, the noisy nature of short‐term data collected with limited resources, and complexities introduced by biotic interactions. Here, we provide a suite of case studies that have considered possible impacts of anthropogenic climate change on Australian terrestrial systems. Our intention is to provide a diverse collection of stories illustrating how Australian flora and fauna are likely responding to direct and indirect effects of anthropogenic climate change. We aim to raise awareness rather than be comprehensive. We include case studies covering canopy dieback in forests, compositional shifts in vegetation, positive feedbacks between climate, vegetation and disturbance regimes, local extinctions in plants, size changes in birds, phenological shifts in reproduction and shifting biotic interactions that threaten communities and endangered species. Some of these changes are direct and clear cut, others are indirect and less clearly connected to climate change; however, all are important in providing insights into the future state of terrestrial ecosystems. We also highlight some of the management issues relevant to conserving terrestrial communities and ecosystems in the face of anthropogenic climate change.     

Application, eco-physiology and biodiversity of anaerobic ammonium-oxidizing bacteria

The demand for new and sustainable systems for nitrogen removal has increased dramatically in the last decade. It is clear that the conventional systems cannot deal with the increasing nitrogen loads in a cost effective way. As an alternative, the implementation of the anammox (anaerobic ammonium oxidation) process in the treatment of wastewater with high ammonium concentrations has been started. The compact anammox reactors can sustain high nitrogen loads without any problems. The highest observed anammox capacity is 8.9 kg N removed m^-3 reactor day^-1. The first 75 m³ anammox reactor is operating in Rotterdam, the Netherlands, combined with the partial nitrification process Single reaction system for High Ammonium Removal Over Nitrite (SHARON). Partial nitrification and anammox can also be combined in one reactor systems like Completely Autotrophic Nitrogen removal Over Nitrite (CANON) or Oxygen Limited Ammonium removal via Nitrification Denitrification (OLAND) where aerobic ammonium-oxidizing bacteria (AOB) and anammox bacteria cooperate under oxygen-limitation. These systems remove about 1.5 kg N m^-3 reactor day^-1. In addition to ammonium, urea can also be converted in the CANON system after a two-week adaptation period. The ecophysiological properties of the anammox bacteria make them very well suited to convert ammonium and nitrite. The K_s values for ammonium and nitrite are below 5 M. However, nitrite above 10 mM is detrimental for the anammox process, and oxygen reversibly inhibits the process at concentrations as low as 1 M. Acetate and propionate can be used by the anammox bacteria to convert nitrite and nitrate, whereas methanol and ethanol severely inhibit the anammox reaction. The enzyme hydroxylamine/hydrazine oxidoreductase (HAO), one of the key enzymes, is located in the anammoxosome, which is a membrane bound organelle. The membranes of the anammox bacteria contain unique ladderane lipids and hopanoids. The bacteria responsible for the anammox reaction are related to the Planctomycetes. The first anammox bacteria were isolated via Percoll centrifugation and characterized as Candidatus Brocadia anammoxidans. Survey of different wastewater treatment plants using anammox specific 16S rRNA gene primers and anammox specific oligonucleotide probes has revealed the presence of at least three other anammox bacteria, which have been tentatively named Candidatus Kuenenia stuttgartiensis, Candidatus Scalindua wagneri and Candidatus Scalindua brodae. A close relative of the latter, Candidatus Scalindua sorokinii was found to be responsible for about 50% of the nitrogen conversion in the anoxic zone of the Black Sea, making the anammox bacteria an important player in the oceanic nitrogen cycle.     

Fibroblast growth factor receptors participate in the control of mitogen-activated protein kinase activity during nerve growth factor-induced neuronal differentiation of PC12 cells.

The current paradigm for the role of nerve growth factor (NGF) or FGF-2 in the differentiation of neuronal cells implies their binding to specific receptors and activation of kinase cascades leading to the expression of differentiation specific genes. We examined herein the hypothesis that FGF receptors (FGFRs) are involved in NGF-induced neuritogenesis of pheochromocytoma-derived PC12 cells. We demonstrate that in PC12 cells, FGFR expression and activity are modulated upon NGF treatment and that a dominant negative FGFR-2 reduces NGF-induced neuritogenesis. Moreover, FGF-2 expression is modulated by NGF, and FGF-2 is detected at the cell surface. Oligonucleotides that specifically inhibit FGF-2 binding to its receptors are able to significantly reduce NGF-induced neurite outgrowth. Finally, the duration of mitogen-activated protein kinase (MAPK) activity upon FGF or NGF stimulation is shortened in FGFR-2 dominant negative cells through inactivation of signaling from the receptor to the Ras/MAPK pathway. In conclusion, these results demonstrate that FGFR activation is involved in neuritogenesis induced by NGF where it contributes to a sustained MAPK activity in response to NGF.