The bacterium Escherichia coli is commonly associated with the presence of faecal contamination in environmental samples, and is therefore subject to statutory surveillance. This is normally done using a culture‐based methodology, which can be slow and laborious. Nucleic acid amplification for the detection of E. coli DNA sequences is a significantly more rapid approach, suited for applications in the field such as a point of sample analysis, and to provide an early warning of contamination. An existing, high integrity qPCR method to detect the E. coli ybbW gene, which requires almost an hour to detect low quantities of the target, was compared with a novel, isothermal RPA method, targeting the same sequence but achieving the result within a few minutes. The RPA technique demonstrated equivalent inclusivity and selectivity, and was able to detect DNA extracted from 100% of 99 E. coli strains, and exclude 100% of 30 non‐target bacterial species. The limit of detection of the RPA assay was at least 100 target sequence copies. The high speed and simple, isothermal amplification chemistry may indicate that RPA is a more suitable methodology for on‐site E. coli monitoring than an existing qPCR technique.

The selective amplification of E. coli nucleic acid sequences could be used for the early warning of faecal contamination in environmental samples. Modified assays for E. coli DNA and RNA markers are presented with improved integrity and performance over existing methods, and demonstrated using 'ready mixed', preserved reagent mixtures.GeneElute PCR Purification Kit (Sigma, UK) and used directly for RNA synthesis using the Hi Scribe T7 RNA Synthesis Kit (NEB, USA) according to the manufacturers recommended protocol. The synthesised RNA was purified using the RNeasy Mini Kit (Qiagen, UK), and contaminating dsDNA was eliminated using RQ1 RNase-Free DNase (Promega, UK) according to the manufacturers recommended protocol. DNA elimination was confirmed by a null Taqbased PCR. The DNA-free RNA was subsequently purified a second time using the RNeasy Clean-up procedure. The mass of RNA was estimated using a BioAnalyser Instrument, and the RNA 6000 Nano Kit (Agilent, UK). This was used to estimate the number of copies based upon the RNA sequence. A series of RNA copy number standards were prepared by diluting the RNA sample in RT-PCR grade water to between 10 and 10 5 copies per microlitre. Standards were prepared from stock RNA solution immediately prior to use.

New Lines considers a society increasingly drawn to the power of the digital map, examining the conceptual and technical developments of the field of geographic information science as this work is refracted through a pervasive digital culture. This book draws together archival research on the birth of the digital map with a reconsideration of the critical turn in mapping and cartographic thought.

No abstract

Attention draws forward these historical accounts to the present moment of fixation on digital media. This chapter argues that ignoring the rapid pace of mediatization is disastrous for a community-engaged mapping impulse.