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Representatives of the genus Arthrobacter were screened for the presence of plasmids. Four alkane-utilising strains showed at least one plasmid and were tested for resistance to antibiotics and heavy metal salts, citrate and alkane-utilisation and production of bacteriocin. All the strains of Arthrobacter screened were resistant to at least 60 mM arsenate and in addition, the four plasmid carrying strains were also resistant to 20 mM arsenite. Heat- and chemical-induced loss of resistance to these salts and the ability to utilise alkanes or citrate, did not lead to the concomitant loss of any plasmids. A small plasmid of 5.5 kb (pSP1) was found in three representatives. A detailed restriction map of pSP1 suggests it could be useful as a potential cloning vector in this group of organisms.

BioEssaysVolume 8, Issue 6 p. 214-214 Book Review The biotechnological challenge. Edited by S. JACOBSSON, A. JAMISON and H. ROTHMAN. Cambridge University Press, Cambridge, 1986. Pp. 181. $34.50, £22.50 I. J. Higgins, I. J. Higgins Cranfield Biotechnology Centre, Cranfield Institute of Technology, Cranfield, Bedford MK43 0AL, UKSearch for more papers by this author I. J. Higgins, I. J. Higgins Cranfield Biotechnology Centre, Cranfield Institute of Technology, Cranfield, Bedford MK43 0AL, UKSearch for more papers by this author First published: June 1988 https://doi.org/10.1002/bies.950080613AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume8, Issue6June 1988Pages 214-214 RelatedInformation

A biosensor is an analytical device that responds to an analyte in an appropriate sample and interprets its concentration as an electrical signal via a suitable combination of a biological recognition system and an electrochemical transducer. As a result of recent scientific and technological progress, such devices are likely to play an increasingly important role in generating analytical information in all sectors of human endeavour, from medicine to the military. In particular, biosensors will form the basis of cheap, simple devices for acquiring chemical information, bringing sophisticated analytical capabilities to the non-specialist and general public alike. The market opportunities for the rapid exploitation of novel developments in this sector are substantial. Biosensor research is also likely to have a significant impact on the development of modern electronics.

Bacteria, isolated from lakewater and capable of growing at the expense of commercial synthetic 2-stroke lubricant oils released 2-ethylhexanol from this substrate by means of esterases. The alcohol accumulated to approximatedly 6mM in these incubations but was itself mineralized by a strain of Pseudomonas putida isolated from the same lakewater by elective culture. The initial steps in the degradative pathway of 2-ethylhexanol were catalysed by alcohol and aldehyde dehydrogenases. The resultant 2-ethylhexanoic acid was further metabolised via β-oxidation. The accumulation of intermediates in culture fluids facilitated by acrylate addition and higher isocitrate lyase activities in cell extracts, suggested that 2-ethylhexanoic acid was cleaved to two butyrate moieties which were then further metabolised to acetate. The pathway shows the organism has an interesting β-oxidation system capable of utilizing branched substrates.

There is a need in many areas of human activity for simple, rapid, reliable, in situ chemical analysis. One approach to achieving such an analytical revolution involves the exploitation of biological systems in association with electronic technology. This contribution briefly describes some recent work in this laboratory aimed at developing amperometric devices.

An oil-degrading bacterium identified as Acinetobacter lwoffi was isolated by elective culture on North Sea Forties crude oil from an activated sludge sample. It grew on a wide range of n-alkanes (C12−C28) and 1-phenylalkanes, including 1-phenyldodecane, 1-phenyltridecane and 1-phenyltetradecane. The organism degraded 1-phenyldodecane to phenylacetic acid which was further metabolized via homogentisic acid, whilst 1-phenyltridecane was transformed to trans-cinnamic and 3-phenylpropionic acid which were not further metabolized. Evidence dence is presented for a relationship between aromatic amino acid catabolism and 1-phenyldodecane degradation in this organism.

Relief of copper deficiency during growth promotes the proliferation of intracytoplasmic membranes together with synthesis of particulate methane mono-oxgenase (MMC) inMethylosinus trichosporium OB3b. Particulate MMO functionsin vitro (in cell-free extracts and membrane preparations) with either succinate or NADH as electron donor but soluble MMO functions only with NADH.

Cell-free extracts of Methylosinus trichosporium 0B3b (MT 0B3b) containing the soluble, broad specificity methane mono-oxygenase (MMO) have been shown to catalyse yet another type of reaction : O-dealkylation. Several 4-substituted anisoles were investigated as substrates, all showed O-demethylation to varying extents by cell-free extracts of the bacterium. This catalytic ability is common to organisms grown on either methane or methanol as sole carbon source, although the rates of biotransformation are lower for the latter. O-demethylation of anisole itself was inhibited (> 99%) by ethyne, a known MMO inhibitor, strongly indicating that the MMO is the enzyme responsible for this catalysis.

The intracellular location of methane mono-oxygenase (MMO) (soluble or particulate) in Methylosinus trichosporium OB3b is dependent on the availability of copper in the growth medium. Raising the Cu2+ concentration from 1 μm to 5 μm effected a transition from soluble to particulate MMO activity, and changes in major cell polypeptides were observed on SDS-polyacrylamide gels. Organisms containing soluble MMO oxidized a wide range of substrates including n-alkanes, n-alkenes, aromatic and alicyclic compounds. By contrast, organisms containing particulate MMO did not oxidize aromatic or alicyclic compounds. These observations provide further evidence that the two types of MMO are fundamentally different.

In vivo 13C NMR has been used to observe metabolism of exogenously supplied methanol by suspensions of Methylosinus trichosporium OB3b grown under a variety of conditions. Formaldehyde, formate and bicarbonate ions were the only metabolites of methanol to be detected. Accumulation of formaldehyde was observed only with suspensions grown under conditions which yield particulate, membrane-bound, methane mono-oxygenase (MMO). Ethyne abolished MMO activity, partially inhibited methanol oxidation in whole organisms, and prevented growth of the organism on methanol (1%, v/v) in batch culture. Oxidation of ethanol, a substrate of methanol dehydrogenase, was not affected by ethyne. Ethyne caused accumulation of formaldehyde in all suspensions of the organism incubated with methanol, although oxidation of exogenously added formaldehyde was not affected. These observations are consistent with the proposal that in M. trichosporium OB3b both MMO and methanol dehydrogenase oxidize exogenously supplied methanol and suggest that the further oxidation of formaldehyde is stimulated by the consumption of reducing equivalents by MMO.

AbstractMechanistic aspects of the mode of action of the soluble monooxygenase system of Methylosinus trichosporium OB3b have been investigated. The hydroxylation of 4‐deuteroanisole in the 4‐position was shown to proceed via an NIH shift with a deuterium retention of 66 %, indicative of an epoxide intermediate. Isotopic studies using ethylbenzene and ethylbertzene‐d10 showed an isotopic effect, kH/kD = 4.5 for benzylic hydroxylation, and an inverse isotopic effect, kH/kD = 0.75 for arene hydroxylation. It is suggested that a stepwise mechanism (hydrogen abstraction and hydroxylation) could be involed.