Glomus intraradices and Gigaspora margarita arbuscular mycorrhizal associations differentially affect nitrogen and potassium nutrition of Plantago lanceolata in a low fertility dune soil

Two controlled microcosm experiments aimed at a critical re-assessment of the contributions of divergent arbuscular mycorrhizal (AM) fungi to plant mineral nutrition were established that specifically targeted Plantago lanceolata–Glomus intraradices (B.B/E) and –Gigaspora margarita (BEG 34) symbioses developed in a native, nutrient limited, coastal dune soil. Plant tissue nitrogen (N), phosphorus (P) and potassium (K) status as well as plant growth parameters and levels of mycorrhizal colonization were assessed at harvest. In addition to the general well-established mycorrhizal facilitation of P uptake, the study was able to demonstrate a G. intraradices-specific contribution to improved plant nitrogen and potassium nutrition. In the two respective experiments, G. intraradices-inoculated plants had 27.8% and 40.8% more total N and 55.8% and 23.3% more total K when compared to Gi. margarita inoculated counterparts. Dissimilar overall contribution of the two isolates to plant nutrition was identified in AM-genus specific differences in plant tissue N:P:K ratios. G. intraradices inoculated and non-mycorrhizal plants generally exhibited N:P:K ratios indicative of P limitation whereas for Gi.margarita mycorrhizal plants, corresponding ratios strongly implied either N or K limitation. The study provides further evidence highlighting AM functional biodiversity in respect to plant nutrient limitation experienced by mycorrhizal P. lanceolata in an ecologically relevant soil system.

Bifidobacterium scardovii sp. nov., from human sources

Five strains of an unusual catalase-negative Gram-positive asporogenous rod-shaped bacterium from human sources were subjected to a polyphasic taxonomic study. The presence of fructose-6-phosphate phosphoketolase, a key enzyme of bifidobacterial hexose metabolism, indicated the strains were members of the genus Bifidobacterium but they did not correspond to any of the recognized species of this genus on the basis of biochemical profiles and whole-cell protein analyses. Comparative 16S rRNA gene sequencing confirmed the placement of the isolates in the genus Bifidobacterium, and demonstrated they represent a hitherto unknown subline within the genus displaying > 5% sequence divergence with recognized species. Based on both phenotypic and phylogenetic criteria, it is proposed that the isolates recovered from human sources be classified as a new species, Bifidobacterium scardovii sp. nov.; the type strain is CCUG 13008T (= DSM 13734T).

Characterization of some strains from human clinical sources which resemble “Leptotrichia sanguinegens”: description of Sneathia sanguinegens sp. nov., gen. nov.

Three strains of a gram-negative, blood or serum requiring, rod-shaped bacterium recovered from human clinical specimens were characterised by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing showed the unknown rod-shaped strains are members of the same species as some fastidious isolates recovered from human blood specimens and previously designated "Leptotrichia sanguinegens". Based on phylogenetic and phenotypic evidence, it is proposed that the isolates from human sources be classified in a new genus Sneathia, as Sneathia sanguinegens gen. nov., sp. nov. The type strain of Sneathia sanguinegens is CCUG 41628T.

3D scanning by multiple fan beam X-ray sources and sensors

*** Purpose – Computer tomography (CT) for 3D reconstruction entails a huge number of coplanar fan-beam projections for each of a large number of 2D slice images, and excessive radiation intensities and dosages. For some applications its rate of throughput is also inadequate. A technique for overcoming these limitations is outlined. *** Design methodology/approach – A novel method to reconstruct 3D surface models of objects is presented, using, typically, ten, 2D projective images. These images are generated by relative motion between this set of objects and a set of ten fanbeam X-ray sources and sensors, with their viewing axes suitably distributed in 2D angular space. *** Findings – The method entails a radiation dosage several orders of magnitude lower than CT, and requires far less computational power. Experimental results are given to illustrate the capability of the technique *** Practical implications – The substantially lower cost of the method and, more particularly, its dramatically lower irradiation make it relevant to many applications precluded by current techniques *** Originality/value – The method can be used in many applications such as aircraft hold-luggage screening, 3D industrial modelling and measurement, and it should also have important applications to medical diagnosis and surgery.

Issues in the assimilation of the sources of a trace gas by inverse modelling

The problem of reconstructing the (otherwise unknown) source and sink field of a tracer in a fluid is studied by developing and testing a simple tracer transport model of a single-level global atmosphere and a dynamic data assimilation system. The source/sink field (taken to be constant over a 10-day assimilation window) and initial tracer field are analysed together by assimilating imperfect tracer observations over the window. Experiments show that useful information about the source/sink field may be determined from relatively few observations when the initial tracer field is known very accurately a-priori, even when a-priori source/sink information is biased (the source/sink a-priori is set to zero). In this case each observation provides information about the source/sink field at positions upstream and the assimilation of many observations together can reasonably determine the location and strength of a test source.

Information sources and advice used by small business tenants when leasing commercial property

Many small businesses lease commercial premises. The terms of a lease can affect the ability of the business to grow and adapt and have an impact on cashflow. Ensuring that they have the information with which to negotiate terms is part of the UK government policy focus on small businesses. Such information is most effectively disseminated through the sources of advice that small businesses use during the leasing process. Therefore these sources of advice need identifying. An interview survey of small business tenants who have recently taken leases provides initial results that suggest small businesses do not seek out advice during the leasing process or see the need to be better informed. The only formal professional input is from solicitors but this is not until after the main commercial terms have been agreed. The landlords’ letting agents play a key, but ambiguous, role in providing information as well as advice. These results suggest that the most effective way of disseminating information by government could be via the letting agents, the very people with whom the tenants are negotiating.