Biodegradation of the Alkaline Cellulose Degradation Products Generated during Radioactive Waste Disposal.

The anoxic, alkaline hydrolysis of cellulosic materials generates a range of cellulose degradation products (CDP) including α and β forms of isosaccharinic acid (ISA) and is expected to occur in radioactive waste disposal sites receiving intermediate level radioactive wastes. The generation of ISA's is of particular relevance to the disposal of these wastes since they are able to form complexes with radioelements such as Pu enhancing their migration. This study demonstrates that microbial communities present in near-surface anoxic sediments are able to degrade CDP including both forms of ISA via iron reduction, sulphate reduction and methanogenesis, without any prior exposure to these substrates. No significant difference (n = 6, p = 0.118) in α and β ISA degradation rates were seen under either iron reducing, sulphate reducing or methanogenic conditions, giving an overall mean degradation rate of 4.7×10−2 hr−1 (SE±2.9×10−3). These results suggest that a radioactive waste disposal site is likely to be colonised by organisms able to degrade CDP and associated ISA's during the construction and operational phase of the facility

An in vivo platform to select and evolve aggregation-resistant proteins

Protein biopharmaceuticals are highly successful, but their utility is compromised by their propensity to aggregate during manufacture and storage. As aggregation can be triggered by non-native states, whose population is not necessarily related to thermodynamic stability, prediction of poorly-behaving biologics is difficult, and searching for sequences with desired properties is labour-intensive and time-consuming. Here we show that an assay in the periplasm of E. coli linking aggregation directly to antibiotic resistance acts as a sensor for the innate (un-accelerated) aggregation of antibody fragments. Using this assay as a directed evolution screen, we demonstrate the generation of aggregation resistant scFv sequences when reformatted as IgGs. This powerful tool can thus screen and evolve ‘manufacturable’ biopharmaceuticals early in industrial development. By comparing the mutational profiles of three different immunoglobulin scaffolds, we show the applicability of this method to investigate protein aggregation mechanisms important to both industrial manufacture and amyloid disease

Analysis of the flow network in an estaurine benthic community

An intertidal mudflat in the Lynher estuary, Cornwall, U.K. has been the site of intensive investigations of energy flow through its biological compartments, and of interactions between its compartments. Joint (1978) quantified autotrophic and heterotrophic microbial production both in the water column and sediments. Several detailed studies have been made of energy flow within the macrobenthos and meiobenthos (Price & Warwick, 1980a,b; Tear & Price, 1979; Warwick, 1981; Warwick & Price, 1975, 1979). Field manipulations (caging experiments) have been conducted to investigate trophic relationships between the faunal and floral components (Warwick et al., 1982; Gee et al., 1985). The results of these and other unpublished studies have been assembled into a steady state energy flow diagram and a dynamic simulation model of the benthic system by Warwick et al (1979) in which most of the flows between compartments have been actually measured rather than assumed, and these models have now found their way into a number of authoritative texts (e.g. Longhurst, 1981; Mann, 1982)

Secondary production of the benthos in an estuarine environment

Several projects relating directly or indirectly to energy flow through the benthic community on a mud-flat in the Lynher estuary, Cornwall, U.K. have been integrated by using two methods, firstly a steady-state energy-flow diagram and secondly a dynamic simulation model, in order to provide a better understanding of ecosystem function and as an aid to research planning. For each macrofauna species and meiofauna group an energy budget has been constructed in the form C = P + R + F + U (IBP terminology). This information, together with values for primary inputs of carbon, has enabled us to construct a quantitative diagram representing the flow of carbon between the faunal components of 1 m2 of mud over 1 year. The net annual production of macrofauna is 5.46 g C m-2, and of meiofauna 20•17 g C m-2. Of the meiofauna production, 3•34 g is utilized within the system, so that 16•83 g remains available to mobile carnivores. The macrofauna ingest 55•74 g of primary carbon annually, and the meiofauna 107•09 g. However, the meiofauna standing crop is only 0•49 times that of the macrofauna. Nematodes and copepods are energetically the most important meiofauna groups. Having achieved realistic simulations of secondary production of deposit-feeders, filter-feeders, Nephtys and meiofauna, it has been possible to investigate the effect on the system as a whole of a variety of hypothetical trophic relationships which are poorly understood, particularly the interactions between meiofauna and macrofauna. The growth of Nephtys on different diets is given as an example