Beach litter sourcing: A trawl along the Northern Ireland coastline.

Fourteen non-recreational coastal locations in Northern Ireland were investigated as to whether beach litter deposition was related to seasonal or site specific factors. Litter items were counted in 100m width transects and 1km strand-line surveys over a five-season period (autumn to autumn). Survey sites comprised fishing ports; estuarine areas, north (high energy) and east coast (low energy) beaches. Fishing ports accumulated the most litter. In the 100m beach surveys, plastics, string and cord, bottle caps, food items, rope, and drink containers dominated. In strand-line surveys, large plastic pieces were dominant, followed by rope, string and cord, strapping bands (absent on beach surveys), cloth, wood (mainly pallets, fish boxes) and metal items. Multivariate analyses revealed major litter category differences between the ports and all other sites, with a lesser distinction between exposed and estuarine sites. There was no simple coastline trend and no apparent effect of seasonality between samples.

From a millennium base line to 2012: beach litter changes in Wales.

Forty-five beaches at 41 bathing area locations in Wales were analysed for litter in 2000 and 2012, via a standard seven category checklist. Fourteen resorts, 2 urban, 11 village, 15 rural 3 remote, were graded, A to D. A grade beach numbers changed from 5 to19; B, 27 to 24; C, 9 to 2; D, 4 to 0, many beaches maintaining their current status. Assuming trend continuance within the next 12 years, the A:B grade ratio would approach equilibrium of 44:56, with no grade C or D beaches. Recreational litter was ubiquitous; fishing materials prevalent along Cardigan Bay. New water treatment plant investment reduced sewage related debris. Despite apparent increased awareness of beach litter, improving visitor behaviour through information/education should be a future priority. Removing a few gross items could improve beach grades at little cost to local authorities and benefits to the Welsh economy.

Removal of organic matter and nitrogen in an horizontal subsurface flow (HSSF) constructed wetland under transient loads.

A monitoring campaign in a horizontal subsurface flow constructed wetland under the influence of transient loads of flow-rate, organic matter, nitrogen and suspended solids showed an irregular removal of COD and TSS and lower both removal efficiencies and mass removal rates than the ones observed in other studies for similar operating conditions. This circumstance is associated to the presence of large amount of particulate organic matter from non-point sources. The mass removal rate of ammonia increased 39% as both the water and soil temperatures increased from weeks 1-8 to weeks 9-14. A good correlation between mass load and mass removal rate was observed for all measured parameters, which attests a satisfactory response of the bed under to transient loads.

The effect of ZD1839 (Iressa), an epidermal growth factor receptor tyrosine kinase inhibitor, in combination with cisplatin, on apoptosis in SCC-15 cells.

The aim of this study was to determine the effect of ZD1839 on growth and apoptosis in SCC-15 (a human head and neck cancer cell line) lone, or in combination with cisplatin. High expression of the epidermal growth factor receptor has been implicated in the development of squamous cell carcinomas of head and neck. ZD1839 ('Iressa') is an orally active, selective epidermal growth factor receptor tyrosine kinase inhibitor that blocks signal transduction pathways implicated in proliferation and survival of cancer cells, and other host-dependent processes promoting cancer growth. Here, growth arrest was observed with 3.64 microm ZD1839. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (sMTT) viability assay revealed a significant decrease (P < 0.001) in the percentage of surviving cells upon treatment with ZD1839 and cisplatin compared with cisplatin or ZD1839 on their own. Combined therapy of 3.64 microm ZD1839 for 24 h, prior to administration of 100 microm cisplatin, significantly (P < 0.001) and additively increased the cytotoxicity effect of cisplatin. p53-independent apoptosis was seen with cisplatin treatment, a novel finding. These data support the use of ZD1839 in anti-cancer therapy, and particularly in combination therapy. Cisplatin may induce p53-independent apoptosis. Over-expression of Bcl-2 in head and neck squamous cell carcinoma tumour cell lines is unlikely to be a general mechanism to protect these cells from apoptosis.

An evaluation of 18S rDNA approaches for the study of fungal diversity in grassland soils.

Fungal community structure and diversity in two types of agricultural grassland soil were investigated by amplified 18S ribosomal DNA restriction analysis (ARDRA) and 18S ribosomal DNA sequence analysis. These two grassland sites represent a species-rich old hay meadow and an agriculturally improved site with low floristic diversity. Two primer sets were used in combination to amplify approximately 550 bp of rDNA from three major fungal groups, the zygomycetes, basidiomycetes, and ascomycetes, and clone libraries were created for each site. 18S ARDRA was used to analyze 170 rDNA clones, and three diversity indices were calculated. A small-scale culturing analysis was also carried out and the most common isolates analyzed using ARDRA and sequence analysis. The soil fungal community revealed by the rDNA approaches was significantly different from that produced by this limited culture-based analysis. Twenty-eight soil-derived clones were sequenced, and many represented fungal taxa rarely reported in culture-based studies. The PCR-based techniques detected differences in diversity between the two fungal communities and changes in patterns of dominance that paralleled higher plant diversity. The results suggest that 18S rDNA-based approaches are a useful tool for initial screening of fungal communities, and that they represent a more comprehensive picture of the community than plate culturing.

An analysis of the instability kinetics of plasmid pHSG415 during continuous culture of Escherichia coli.

The effect of dilution rate on the instability kinetics of Escherichia coli RV308(pHSG415) during glucose-limited continuous culture is examined. Two nonlinear models are fitted to the data, both of which characterize the plasmid-host system in terms of the rate parameters R (for the plasmid segregation rate) and d mu (for the specific growth rate difference between plasmid-free and plasmid-bearing single cells). In the first model, both R and d mu have constant values with respect to time. In the second, either R or d mu is represented as a time-dependent function. Although both models fit the data equally well, it is demonstrated that the constant rate parameter model gives results which appear to be misleading. A comparison is also made among some of the many plasmid instability models (both mass-balance and segregated) which have appeared in the literature. It is found that all of these give identical trajectories and differ only in the definitions of the rate parameters used.

Plasmid replication and maintenance in binary fissile microorganisms.

The mechanisms of nonconjugative plasmid replication (in the single cell) and maintenance (at the population level) are of concern to the microbiologist and to the genetic engineer who wishes to exploit their ability to express cloned genes. This article concentrates mainly on Escherichia coli as the host organism and examines the mechanisms by which both naturally occurring and genetically engineered plasmids persist in populations during periods of growth. Additional strategies to ensure high yields of recombinant product are briefly considered.

A nonlinear technique for the analysis of plasmid instability in micro-organisms.

A nonlinear technique to calculate parameters for segregational instability and differences in cellular growth-rate for plasmid-bearing micro-organisms growing in batch or continuous culture is presented. This method is compared with an approximate technique based upon linear regression. The accuracy and sensitivity of the results are evaluated by use of simulated data and biological data taken from experiments with Pseudomonas aeruginosa(pGSS15) and Escherichia coli(pHSG415). It is demonstrated that the nonlinear analysis gives results which are significantly more accurate and which show much better agreement with the data. Consequently, the new analysis leads to quite different conclusions with regard to the nature of the instability of the plasmid-bearing strain. This method offers an opportunity to study the genetic and physiological aspects of plasmid instability and so aid the design and optimization of cloning vectors.