International Biodeterioration最新文献

Flocoumafen had good rodenticidal action against Apodemus agrarius and Rattus losea. The acute oral LD₅₀ for male A. agrarius and R. losea was 1·22 mg kg⁻¹ and 1·36 mg kg⁻¹ respectively. Flocoumafen bait was more toxic to R. losea than to A. agrarius. At bait concentrations of 0·002–0·005%, flocoumafen had a single-feed potency with mortalities of 90–100% for R. losea and 77·8–100% for A. agrarius. Experimental baits prepared using the manufacturing 0·5% master mix of flocoumafen were palatable to both species.

Hard limestone walls in Jerusalem and marble monuments in Rome were studied. An attempt was made to classify the principal biodeterioration processes in walls facing the prevailing wind and those which were protected from it. In Jerusalem, those that face the prevailing rain-bearing wind become populated by cyanobacteria and cyanophilous lichens. Within c. 100 years white walls are turned to grey or black colour by these organisms. Rain detaches rock particles from the vicinity of the microorganisms at a rate of 1 mm in 200 years. Dark patches on marble monuments in Rome indicate the presence of cyanobacteria. Such biological activity promotes detachment of particles by rain and accelerates weathering leading to pit formation. The estimated rate of pitting is 1 mm per 40 years in the Forum Traianum. To prevent the biodeterioration of limestone and marble monuments the habitats and ecological demands of the various microorganisms must be considered.

Increasing the frequency of misting of flax plants which had been treated with the herbicide glyphosate also tended to increase the numbers of microbial isolates and increase retting. Fungicides, applied at weekly intervals, suppressed the numbers of fungi but increased the numbers of bacterial isolates; they also decreased retting. Numbers and proportions of fungal isolates varied to some extent with treatment but the spectrum of isolates was relatively constant and appeared little influenced by artificial inoculation. Alternaria alternata was the dominant fungal isolate.

Bacteria associated with plants were examined for their ability to use cyclodextrins (CDs) as a unique carbon source. Among 24 strains from eight genera, Xanthomonas were the most active. The cyclodextrin decomposing ability of strains were not related to their taxonomic position. Chemical structure significantly influenced the degradability of cyclodextrins by bacteria. The less rigid ring structure of gamma-CD favoured utilization, whereas methylation led to reduced utilization.

Bacterial contimination on proteinaceous objets d'art such as parchment and mummies exposed to low relative humidity and low oxygen levels has been assessed using a polycarbonate NUCLEPORE filter and incedent light (epifluorescence) microscopy. The technique described is a rapid and sensitive means for observing and evaluating bacterial populations including anaerobic organisms involved in the depolymerization of collagen. Using contaminated 17th century parchment treated to microenvironmental control and modified atmospheres a positive relationship has been found between fluorescence counts and plate colony counts.

Evidence has been presented for the synergism between copper (Cu) and formaldehyde (FA) and isothiazolone (IT) and also for the equivalence of many FA adducts with FA. A distinction as well as a dual site for Cu-IT interaction has been made with both protection from environmental nucleophiles as well as enhancement of antimicrobial activity. Since the major FA dehydrogenase associated with FA resistance is glutathione dependent, the prospect of Cu-glutathione interaction is a probable cause of Cu-FA synergism.

Although there is no clear explanation for the IT-FA synergism, the combination offers many avenues for future exploration.

This paper will review the regulatory requirements for the introduction of new substances in Europe and illustrate where differences exist in USA and Japan.

Registration requirements, which exist in every member state of the EEC for each type of application for new formulations using existing or new biocide active ingredients, will be described with examples. Proposed EEC directives which affect the use of biocide active ingredients will also be described.

The impact of the Preparations Directive for formulations containing biocides will be discussed.

Methods currently in use for the identification of sulphate-reducing bacteria are time-consuming relying on biochemical and cultural characteristics. Two immunological techniques have been developed to identify the bacteria within this group more rapidly. The microtitre plate agglutination assay is simple and inexpensive. Relatively few cross-reactions have been detected and these are within a species. The direct ELISA is even more specific, but is somewhat more costly and requires special equipment and expertise. Both tests would be appropriate for species identification in the sulphate-reducing bacteria.