Toward cell-free biofuel production: Stable immobilization of oligomeric enzymes.

To overcome the main challenges facing alcohol-based biofuel production, we propose an alternate simplified biofuel production scheme based on a cell-free immobilized enzyme system. In this paper, we measured the activity of two tetrameric enzymes, a control enzyme with a colorimetric assay, ß-galactosidase, and an alcohol-producing enzyme, alcohol dehydrogenase, immobilized on multiple surface curvatures and chemistries. Several solid supports including silica nanoparticles (convex), mesopourous silica (concave), diatomaceous earth (concave), and methacrylate (concave) were examined. High conversion rates and low protein leaching was achieved by covalent immobilization of both enzymes on methacrylate resin. Alcohol dehydrogenase (ADH) exhibited long-term stability and over 80% conversion of aldehyde to alcohol over 16 days of batch cycles. The complete reaction scheme for the conversion of acid to aldehyde to alcohol was demonstrated in vitro by immobilizing ADH with keto-acid decarboxylase free in solution.

Chromosomal instability at a mutational hotspot in polyoma middle T-antigen affects its ability to activate the ARF-p53 tumor suppressor pathway.

We have isolated spontaneous mutants of polyoma virus middle T-antigen (PyMT) that do not activate the ARF-p53 pathway based on their inability to block REF52 cell division. The REF52 cells containing these mutants have a flat untransformed morphological phenotype and do not express the ARF protein. The PyMT mutations in the different cell isolates so far analysed occur at a mutational hotspot in the PyMT sequence between nucleotides 1241 and 1249, which contains nine consecutive cytosines. In one set of mutants a single cytosine was deleted, while in another mutant set an additional cytosine was inserted. Both these mutations result in frameshifts, generating altered PyMT proteins containing amino-acid sequences derived from each of the two other alternative reading frames of the polyoma virus early region. Both types of mutations result in the loss of the C-terminal PyMT region containing the membrane-binding hydrophobic region and result is mislocalization of the PyMT mutant proteins. Revertant wild-type PyMT (containing nine cytosines) was easily detected in transformants generated after infection of REF52 cells expressing high amounts of dominant negative p53 with retroviruses containing either mutation. We demonstrate that wild-type PyMT revertants are derived from mutations in the hotspot sequence of the integrated mutant PyMT sequences.

Biosafety: future priorities for research in health care.

Currently the public interest in biosafety issues has focussed on the discussions surrounding the use of genetically modified organisms, very specifically on the use of transgenic plants in agriculture. Although many of the questions raised in connection with genetically modified organisms are of legitimate scientific interest, attention should be drawn back to a number of other more classical biosafety research areas, namely the problem of control of new and reemerging infectious diseases, the need for new vaccines, control of transport and routes of dissemination, biosafety information exchange and networking, where research results are dearly needed. In the area of modern biotechnology new applications such as gene therapy and transgenic animals will be on the list of future priorities for biosafety related activities and research.

The bovine tubercle bacillus.

The bovine tubercle bacillus has always been eclipsed by the much higher incidence and the social and economic importance of its human cousin, as well as by the clinical unimportance of differentiating between the two. Nevertheless, in view of the resurgence of tuberculosis generally, the increase in the number of immunosuppressed individuals (i.e. the AIDS epidemic) and the 'great badger debate', there is renewed interest in it. Briefly, this review explores the history of Mycobacterium bovis and its potential for transmission between cattle and humans.

Stability of high-performance liquid chromatography columns packed with poly(methyloctylsiloxane) sorbed and radiation-immobilized onto porous silica and zirconized silica.

Reversed-phase packing materials were prepared from HPLC silica and from zirconized HPLC silica support particles having sorbed poly(methyloctylsiloxane) (PMOS) as the stationary phase. Portions of zirconized material were subjected to 80 kGy of ionizing radiation. Columns prepared from these packing materials were subjected to 5000 column volumes each of neutral and alkaline (pH 10) mobile phases, with periodic tests to evaluate chromatographic performance. It was shown that the PMOS stationary phase sorbed onto zirconized silica requires an immobilization treatment (such as gamma irradiation) for long term stability while prior surface zirconization of the silica support surface greatly improves the chromatographic stability of the stationary phase when using alkaline mobile phases.

Effects in high-performance liquid chromatography of a high pH in the mobile phase on poly(methyloctylsiloxane) immobilized by gamma-radiation on titanium-grafted silica.

Effects of high-pH environments on a stationary phase prepared by gamma-radiation immobilization of poly(methyloctylsiloxane) on titanium-grafted silica were investigated by HPLC testing with standard sample mixtures. The HPLC parameters indicate good stationary phase stability to 10000 column volumes each of mobile phases with pH of 7, 9 and 12. At pH 13, the efficiency decreases slowly, although reasonably good separations are still possible until increasing flow resistance no longer allows easy passage of the mobile phase.

Microbiological safety cabinets: selection, installation, testing and use.

In the last quarter of the 20th century, there was much confusion and uncertainty amongst microbiologists and managers about the choice, installation, testing and use of the various types of microbiological safety cabinet. This review clarifies these issues, with reference to the latest standards and safe procedures.

Speciation of aqueous chromium(VI) solutions with the aid of Q-mode factor analysis followed by oblique projection.

The identities of the species of chromium(VI) that are present in aqueous solution, their spectra and their equilibria, continue to be a subject of discussion in the literature. In this paper, the composition of the Cr(VI) equilibria was estimated from the UV-vis spectra of dilute potassium dichromate solutions, without any prior knowledge of the quantities of pure components, with the aid of Imbrie Q-mode factor analysis (Q-mode FA) followed by Varimax rotation and Imbrie oblique projection. Combining these results with the k-matrix method, it was possible to obtain the spectra of the individual Cr(VI) species. Sets of 3.3x10(-4) and 3.3x10(-5) mol l(-1) Cr(VI) solutions were studied. In the pH range from 1 to 12, two factors were identified, which were related to the two species, chromate ion (CrO(4)(2-)) and bichromate ion (HCrO(4)(-)). When the analysis was extended to concentrated acid media, another factor appeared, which was related to chromic acid (H(2)CrO(4)). No evidence for the dichromate ion (Cr(2)O(7)(2-)) was seen at the Cr(VI) concentrations used. The spectra of the pure components were obtained and pK values for the first and second chromic acid dissociations were estimated as -0.54 and 5.8, respectively.

Tuberculosis acquired in laboratories and necropsy rooms.

The resurgence of tuberculosis, and the increasing number of cases that are HIV-related and/or multidrug resistant, has renewed interest in the occupational hazards posed by tuberculosis to staff in laboratories and necropsy rooms. A search undertaken using Medline and Pre-Medline identified few comprehensive reviews: the last was published in 1982. Staff may acquire pulmonary infection by inhalation of aerosols and skin lesions through cuts and abrasions. Particular hazards for laboratory staff include specimen containers contaminated on the outside, unfixed sputum smears, and the generation of aerosols during examination procedures. Examination of patients with tuberculosis not diagnosed during life constitutes a particular risk to necropsy room staff. Staff of laboratories and necropsy rooms are estimated to be between 100 and 200 times more likely than the general public to develop tuberculosis. Training in good laboratory practice is the most important aspect of staff protection, especially in resource-poor countries where well-maintained safety cabinets are rarely available. This article summarises requirements and recommendations for safe handling of tuberculous material and the available guidelines for work in developed and resource-poor countries.

Evolution of microbiological safety cabinets.

Microbiological safety cabinets have had a chequered history, often being confused with chemical fume cupboards and cabinets intended to protect cultures from contamination rather than workers from infection. They have suffered from incorrect and inapt names. Much work has been required to determine the levels of air flow necessary to contain infectious particles and to prevent the exhaust of those particles to the environment, and this is considered in historical sequence. Warnings are given about the shortcomings of portable and home-made cabinets. This review traces the evolution of these cabinets, from the time of Robert Koch to the development of good national standards.

Confidential inquiry into quality of care before admission to intensive care.

OBJECTIVE: To examine the prevalence, nature, causes, and consequences of suboptimal care before admission to intensive care units, and to suggest possible solutions. DESIGN: Prospective confidential inquiry on the basis of structured interviews and questionnaires. SETTING: A large district general hospital and a teaching hospital. SUBJECTS: A cohort of 100 consecutive adult emergency admissions, 50 in each centre. MAIN OUTCOME MEASURES: Opinions of two external assessors on quality of care especially recognition, investigation, monitoring, and management of abnormalities of airway, breathing, and circulation, and oxygen therapy and monitoring. RESULTS: Assessors agreed that 20 patients were well managed (group 1) and 54 patients received suboptimal care (group 2). Assessors disagreed on quality of management of 26 patients (group 3). The casemix and severity of illness, defined by the acute physiology and chronic health evaluation (APACHE II) score, were similar between centres and the three groups. In groups 1, 2, and 3 intensive care mortalities were 5 (25%), 26 (48%), and 6 (23%) respectively (P=0.04) (group 1 versus group 2, P=0.07). Hospital mortalities were 7 (35%), 30 (56%), and 8 (31%) (P=0.07) and standardised hospital mortality ratios (95% confidence intervals) were 1.23 (0.49 to 2.54), 1.4 (0.94 to 2.0), and 1.26 (0.54 to 2.48) respectively. Admission to intensive care was considered late in 37 (69%) patients in group 2. Overall, a minimum of 4.5% and a maximum of 41% of admissions were considered potentially avoidable. Suboptimal care contributed to morbidity or mortality in most instances. The main causes of suboptimal care were failure of organisation, lack of knowledge, failure to appreciate clinical urgency, lack of supervision, and failure to seek advice. CONCLUSIONS: The management of airway, breathing, and circulation, and oxygen therapy and monitoring in severely ill patients before admission to intensive care units may frequently be suboptimal. Major consequences may include increased morbidity and mortality and requirement for intensive care. Possible solutions include improved teaching, establishment of medical emergency teams, and widespread debate on the structure and process of acute care.

Safe biotechnology. 8. Transport of infectious and biological materials. Working Party "Safety in Biotechnology" of the European Federation of Biotechnology.

The transport of infectious and biological material is regulated by a number of international organizations. This mini-review has been compiled to increase awareness within the scientific community of problems caused by differences in terminology (such as infectious materials/substances, biological products, diagnostic specimens, genetically modified microorganisms) and certain technical aspects of the main international guidelines, and to assist policy makers in the creation of harmonized guidelines. A list of relevant Internet resources has been compiled.

Safe biotechnology. 7. Classification of microorganisms on the basis of hazard. Working Party "Safety in Biotechnology" of the European Federation Biotechnology.

The current systems for classifying human pathogens on the basis of hazard are well developed and their basic criteria are in general agreement one with another. Of more importance, the safety practices based on these classifications have generally been successful. They have enabled extensive research activities, medical practice and industrial production to be conducted on an ever-increasing scale, involving dangerous microorganisms (e.g. in vaccine production and treatment of infected patients) with a very low incidence of adverse effects on the workers involved and the general public. Although the EU has adopted a harmonised list of agents in groups 1-4 there is as yet no complete agreement among member states and individual microbiologists. The purpose of this paper is to present a historical survey and to discuss the current processes for identifying and classifying the hazards posed by the use of microorganisms in research and technology. This is essential in the design of appropriate methods of counteracting potential risks.

Formaldehyde disinfection in laboratories: limitations and hazards.

Formaldehyde is a substance hazardous to health, specified in Schedule 1 to the British Control of Substances Hazardous to Health Regulations 1988 but still used in laboratories as a preservative and for disinfection of surfaces and spaces. In this paper we review the properties and hazards of formaldehyde and its common laboratory uses, and suggest some precautions and ways of minimising risk from those fumigation procedures that carry the greatest risk of exposure to high levels of the gas.