Orthophosphate analysis by the Fiske-SubbaRow method and interference by adenosine phosphates and pyrophosphate at variable acid pH

ATP, ADP, AMP, and pyrophosphate interfere with colour development in the Fiske-SubbaRow assay procedure. The extent of interference observed is dependent on the pH of the final assay system; small changes in pH at low pH values lead to large variations in the amount of ATP interference. Addition of excess ammonium molybdate and neutralisation of any previous acid additions (such that the pH is maintained constant throughout all assay procedures) removes interference and P₁ can be estimated in the presence of relatively high ATP concentrations.     

Chimpanzee 'folk physics': bringing failures into focus

Differences between individuals are the raw material from which theories of the evolution and ontogeny of cognition are built. For example, when 4-year-old children pass a test requiring them to communicate the content of another's falsely held belief, while 3-year-olds fail, we know that something must change over the course of the third year of life. In the search for what develops or evolves, the typical route is to probe the extents and limits of successful individuals' ability. Another is to focus on those that failed, and find out what difference or lack prevented them from passing the task. Recent research in developmental psychology has harnessed individual differences to illuminate the cognitive mechanisms that emerge to enable success. We apply this approach to explaining some of the failures made by chimpanzees when using tools to solve problems. Twelve of 16 chimpanzees failed to discriminate between a complete and a broken tool when, after being set down, the ends of the broken one were aligned in front of them. There was a correlation between performance on this aligned task and another in which after being set down, the centre of both tools was covered, suggesting that the limiting factor was not the representation of connection, but memory or attention. Some chimpanzees that passed the aligned task passed a task in which the location of the broken tool was never visible but had to be inferred.     

Molecular detection and beta-glucuronidase expression of gus-marked Bacillus subtilis L-form bacteria in developing Chinese cabbage seedlings

AIM: To detect L-form bacteria in developing Chinese cabbage seedlings. METHODS AND RESULTS: Stable Bacillus subtilis L-forms were genetically modified to express the gus gene (encoding beta-glucuronidase). Germinated seeds of Chinese cabbage were soaked in mannitol based suspensions of the L-form bacteria or with mannitol alone and after washing were grown in aseptic conditions on plant growth medium. Histochemical staining of beta-glucuronidase activity (X-gluc) and Polymerase Chain Reaction (PCR) detection of the gus gene were achieved in the L-form associated seedlings. beta-Glucuronidase was localized in discrete spots, mainly in the roots with staining, and was also observed in the cotyledons and base of stems. Correlation was observed between PCR detection of the gus gene and histochemical staining with detection in similar tissues. Stable L-form bacteria were non-culturable after their association with plant material. CONCLUSIONS: The gus reporter gene system with its associated histological staining for enzyme activity was used successfully for detecting B. subtilis L-form bacteria in plant material. SIGNIFICANCE AND IMPACT OF THE STUDY: These molecular marked L-forms should provide a specific and sensitive technique for detecting L-form bacteria in planta and offer a method for further understanding the L-form/plant association.     

Genetic identification of immigrants to the Scandinavian wolf population

Continued gene flow is fundamental to the survival of small, isolated populations. However, geography and human intervention can often act contrary to this requirement. The Scandinavian wolf population is threatened with a loss of genetic variation yet limited in the accessibility to new immigrants by the geographical distance of this peninsular population from its nearest neighbouring population and by human reluctance to allow wolves in the northern reindeer-breeding areas. In this study, we describe the identification of immigrants into this population using autosomal microsatellites, and maternally inherited mtDNA. Samples of 14 wolves collected in the “dispersal corridor” in northern Sweden in 2002–2005 were compared with 185 resident Scandinavian wolves and 79 wolves from the neighbouring Finnish population. We identified four immigrant wolves, suggesting some westward migration, although only one of these is likely to still survive. The integration of such immigrants into the breeding population is necessary to assure the long-term survival of this isolated and inbred population and highlights the importance of genetics techniques to the management of threatened populations.     

Investigation of two new putative pheromone components of the invasive Australian redback spider,Latrodectus hasseltii,with potential applications for control

The Australian redback spider, Latrodectus hasseltii preys on at least 10 endemic species in New Zealand, highlighting a need for control. Male redbacks are attracted to virgin females by an airborne pheromone. The aim of this study was to analyse the response of male redback spiders to two volatile chemicals found on the silk of virgin but not mated females, to determine whether these compounds constitute components of the airborne pheromone. Mature male redback spiders were placed in an olfactometer where they had a choice of two stimuli. We compared their response to paired combinations of a control, virgin silk, butyric acid and isovaleric acid. Male redbacks responded equally strongly to butyric acid and virgin silk, in terms of time spent near the stimulus. The identification of butyric acid as a component of the airborne sex pheromone of L. hasseltii provides the groundwork for developing a pheromone-based control.