Purification, properties and comparative specificities of the enzyme prolyl-transfer ribonucleic acid synthetase from Phaseolus aureus and Polygonatum multiflorum

1. A prolyl-s-RNA synthetase (prolyl-transfer RNA synthetase) has been purified about 250-fold from seed of Phaseolus aureus (mung bean), a species not producing azetidine-2-carboxylic acid, and more than 10-fold from rhizome apices of Polygonatum multiflorum, a liliaceous species containing azetidine-2-carboxylic acid. The latter enzyme was unstable during ammonium sulphate fractionation. 2. The enzymes exhibited different substrate specificities towards the analogue. That from Phaseolus, when assayed by the ATP-PP(i) exchange, showed azetidine-2-carboxylic acid activation at about one-third the rate with proline. Both labelled imino acids gave rise to a labelled aminoacyl-s-RNA. The enzyme from Polygonatum, however, activated only proline. 3. The enzyme from Polygonatum also formed a labelled prolyl-s-RNA with Phaseolus s-RNA but at a lower rate than when the Phaseolus enzyme was used. No reaction occurred when the Phaseolus enzyme was coupled with Polygonatum s-RNA, and only a very slight one was observed when both enzyme and s-RNA came from Polygonatum. 4. Protein preparations from seeds of Pisum sativum, another species not producing azetidine-2-carboxylic acid, also activated the analogue in addition to proline, whereas those from rhizome and seeds of Convallaria, the species from which the analogue was originally isolated, failed to activate it. However, a liliaceous species not producing the analogue, Asparagus officinalis, activated it. 5. Of the other proline analogues investigated, only 3,4-dehydro-dl-proline and l-thiazolidine-4-carboxylic acid were active with the enzyme preparation from Phaseolus. 6. pH optima of 7.9 and 8.4 were established for the enzymes from Phaseolus and Polygonatum respectively. 7. The Phaseolus enzyme was specific for ATP and PP(i). Mn(2+) partially replaced the requirement for Mg(2+) as cofactor. Preincubation with p-chloromercuribenzoate at a concentration of 0.5mm or higher produced over 99% inhibition of the Phaseolus enzyme. One-half the enzymic activity was destroyed by preheating for 5min. at 62 degrees in tris-hydrochloric acid buffer, pH7.9. 8. All experimental evidence supports the hypothesis that azetidine-2-carboxylic acid and proline are activated by the same enzyme in Phaseolus preparations, whereas the analogue was inactive in all Polygonatum preparations. The possible nature of this different substrate behaviour is discussed.

New indicator approaches for effective urban air quality management

Measurements of urban air quality at monitoring stations in developed countries have frequently involved the criteria gaseous pollutants, particulates, hazardous air pollutants, perceived air quality and relevant meteorological conditions. Large numbers of indicators have therefore been established to quantify emissions, concentrations and environmental and human health impacts of each of these groups of substances. To simplify the data for management, several indicators have been grouped together to form urban air quality indices but the weightings of individual variables is contentious. In industrialising and developing countries, data may be limited and traditional air pollutant indicators cannot often be constructed. The emphasis therefore has to be placed on the development of policy-relevant indicators, such as Response Indicators that reflect different policy principles for regulating air pollutant emissions. Indices that quantify the air quality management capabilities and capacities at the city level provide further useful decision-relevant tools. Four sets of indices, namely, 1. air quality measurement capacity, 2. data assessment and availability, 3. emissions estimates, and 4. management enabling capabilities, and a composite index to evaluate air quality management capability, were constructed and applied to 80 cities. The indices revealed that management capability varied widely between the cities. In some of the cities, existing national knowledge on urban air quality could have been more effectively used for management. It was concluded that for effective urban air quality management, a greater emphasis should be given, not just to monitoring and data capture programmes, but to the development of indicators and indices that empower decision-makers to initiate management response strategies. Over-reliance on restricted, predetermined sets of traditional air quality indicators should be avoided.

Assessment of exposure to chemical contaminants in water and food

The main questions on the validity of the studies and routine monitoring (e.g., in the scope of the WHO/UNEP GEMS programme) assessing exposure to chemicals through water and food (i.e., through digestion) relate to the following. (a)

SAMPLING

variations due to sampling strategy and approach usually exceed analytical errors. (b)

MEASUREMENT

quality assessment and quality control (QA/QC) procedures are essential. However, potential limitations of measurement errors resulting from implementation of these procedures should be kept in perspective with other errors and confounding factors. (c)

METHODOLOGY

which depends on the variability of the intake patterns in the population, as well on the adequacy of the information on the consumption of food of a specified type as an indicator of the intake of a specific chemical. These factors should be considered in particular in studies using 'food basket' methods. Whenever possible, structure of the population in respect to the factors determining typical diet should be registered. (d) Form of reporting: limiting possibilities for re-analysis of the exposure estimates. In conclusion, the routinely collected data on exposure through food and water should be used with care in epidemiological studies. Assessment of the exposure conducted specially for the epidemiological study should consider possible changes of the diet with time. The data on confounders are crucial for exposure estimates.

The role of biomarkers in environmental assessment (4). Terrestrial plants

The potential of metabolites, enzymatic processes and changes in plant performance as biomarkers in environmental assessment is reviewed. Biomarkers may be used as an early warning system of specific or general stress at each biological level, from molecules to ecosystems. The sensitivity of a species and, thus, the efficiency of a biomarker will depend on the degree of already present adaptation to environmental stress and on the homogeneity of the investigated population. Biomarkers for specific environmental stresses are scarce; better known are biomarkers for environmental stress complexes such as heavy metals, physiological drought and extreme temperature or biomarkers as a reaction on a full scale of environmental stresses. It is argued that a battery of biomarkers is necessary to evaluate chemical hazards to species.

Infections and infection control among residents of eight rural Wisconsin nursing homes

During 1984 and 1985, an initial prevalence survey and six consecutive months of comprehensive prospective surveillance were conducted in eight rural Wisconsin nonproprietary nursing homes managed by eight nonprofit hospitals in the same communities. Our purpose was to define the infections in the residents and the infection control programs in the nursing homes. The initial prevalence survey analyzed the records of all 403 residents of the eight nursing homes. The average resident was 83.4 years old and had 3.4 chronic diseases noted on the chart. During this initial survey, 52 (12.9%) of the residents were found to have 56 active infections of all types. During six consecutive months of comprehensive surveillance in the eight nursing homes, 265 episodes of acute infection were found for an overall incidence of 10.7 infections per 100 resident months. Clusters of infection by site, pathogen, or month of onset were quite uncommon throughout the study. Susceptibility testing of organisms recovered from infections failed to reveal any clinically important resistance patterns. Because nursing homes are different in many respects from hospitals, appropriately modified definitions and infection control strategies are required for nursing homes and their residents.

Nosocomial infections in 15 rural Wisconsin hospitals--results and conclusions from 6 months of comprehensive surveillance

Fifteen rural Wisconsin acute care community hospitals with an average approved bed size of 55 and an average daily census of 28 patients participated in a nosocomial infection control project. Each hospital Infection Control Practitioner (ICP) was trained and conducted prospective nosocomial infection surveillance on all patients admitted to the hospital for 6 consecutive months between May 1, 1984 and April 30, 1985. Two hundred twenty nosocomial infections were reported among 13,420 discharged patients for an incidence rate of 1.64 infections per 100 discharged patients. One hundred sixty-four patients had one nosocomial infection. Twenty-three patients had two or more. Infection rates were highest among gynecology--4.9% and general surgery patients--4.0%, and lowest among newborns--0.3% and pediatric patients--0%. 39.7% of the infections were of the urinary tract, 27.9% of surgical wounds, 16% pneumonia, and 1.4% primary bacteremia. The other infections were in seven additional sites. Risk factors associated with acquisition of infections included old age, urinary catheterization, and/or a surgical procedure. The overall nosocomial surgical wound infection incidence for inpatient procedures was 1.9%, with incidences of 0.4% for hernia repair, 1.3% for cholecystectomy, 3.3% for appendectomy, 4.0% for total abdominal hysterectomy, and 3.9% for cesarean sections. The incidence of nosocomial infections was 2.7 infections per 100 discharged patients age 65 years or over and 0.9 infections per 100 discharged patients less than 65 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Nosocomial infection prevalence, risk and control in small community and rural hospitals

Between 1972 and 1973, Britt and colleagues conducted 1-day infection prevalence surveys in 18 hospitals each with fewer than 75 beds and all located in the rural intermountain west. The lessons learned from that study were incorporated into a book chapter entitled “Infection Control in Small Hospitals” by Dr. Britt. Since that study no substantial nor systematic review of nosocomial infections in small community or rural hospitals has been reported. A recent editorial in Infection Control posed four questions that still needed to be answered for the smaller (less than 100-bed) hospital:

1. Given the statistical realities of small hospitals, what types of surveillance methods—periodic prevalence surveys, general surveillance, focused surveillance, etc.—are the most reliable? Are any of them necessary?

2. Which of the many infection control practices recommended by the CDC, the Joint Commission on Accreditation of Hospitals, and others are applicable to small hospitals?

3. What resource sharing of existing expertise, from larger hospitals, health departments, groups such as the Association of Practitioners of Infection Control and the Society of Hospital Epidemiologists of America, and others can be developed for smaller hospitals in cost effective and realistic ways?

4. Should smaller hospitals be required to have the same type of multidisciplinary infection control committees required of larger hospitals or can the responsibilities of the committee be delegated to a smaller group such as one nurse and one staff physician?

The purpose of this report is to provide detailed infection control information obtained from 15 hospitals located in rural areas of Southwestern Wisconsin. This article will focus on data derived from an initial comprehensive prevalence survey that replicated the Britt study in the Wisconsin sites in 1983. Additional data were derived from ongoing bi-monthly prevalence studies done over 6 consecutive months in each of the 15 rural hospitals. Data from 6 months of ongoing comprehensive surveillance from each of the 15 hospitals and final conclusions from the project will be the subject of a subsequent paper.

Hallucinations of widowhood

Widowed residents of two nursing homes who were oriented to person, time, and place were interviewed to determine the extent to which they had hallucinatory experiences of their deceased spouse. Fifty-two interviews were completed with 46 widows and six widowers. Results are reported for the widows. Twenty-eight (61%) of the widows reported hallucinatory experiences of their deceased spouse. Twenty-four (86%) of the widows described the experiences as good or helpful. Thirteen (46%) reported that the experiences continue to happen. Nineteen (54%) of the widows had never discussed the experiences with anyone before this study. These results are surprisingly similar to previously published findings by Rees in Wales and suggest that these experiences are more common in the United States than has been recognized.

The accumulation and assimilation of dimethylselenide by four plant species

Plants of Agrostis tenuis Sibth., Hordeum vulgare L., Lycopersicon esculentum Mill. and Raphanus sativus L. were grown hydroponically in sealed systems and fumigated with 8 μg m(-3) [(75)Se]-dimethylselenide. The accumulation of (75)Se was measured and the shoot tissues were extracted to examine the products of the (75)Se assimilation. Characteristic differences were observed between species in the accumulation of (75)Se and the transport from shoots to roots. High-voltage electrophoresis and chromatography of extracts made with 80% aqueous ethanol revealed the presence of inorganic selenite as an assimilation product as well as the selenium analogues of glutathione and methionine. Extensive incorporation of (75)Se into protein-bound selenomethionine was observed in all plant species.

Study of psychological characteristics of a workers' compensation sample using the MMPI and Million Clinical Multiaxial Inventory

47 Workers' Compensation claimants who had been referred for psychological evaluation were administered the Wechsler Adult Intelligence Scale, the Minnesota Multiphasic Personality Inventory, and the Millon Clinical Multiaxial Inventory. The subjects were divided into four diagnostic groups based on the type of injury claimed: head injury, psychiatric “stress and strain,” low back pain, and miscellaneous. Analysis of variance and discriminant analysis were performed on test data comparing the exclusive diagnostic categories; none of these variables displayed any significant differences. Mean profiles on each personality test were derived for each diagnostic group and showed amazingly similar patterns with interesting clinical elevations. Psychological characteristics displayed by all groups included passive dependence, depression, anxiety, and social introversion. The findings are discussed in terms of the use of these instruments in making differential diagnosis, identification of high-risk individuals for filing insurance claims, and the issue of malingering.

Geochemistry and ecology

This paper discusses the importance of geochemistry as a determining factor in the evolutionary development of plant assemblages. Three contrasting examples of geochemical systems are described and considered in relation to their effects on plant growth and development. Soils derived from serpentines may contain elevated and sometimes toxic concentrations of Cr and Ni depending on mineral composition and weathering processes. These conditions have so modified plant growth during the past few million years that specialized floras have evolved on particular sites. Extensive areas throughout the world contain high concentrations of Se but these have not always been accompanied by the development of specific floras. Geochemistry can help explain how Se-specific floras have developed in several Western States of America but are absent on Se-rich sites in the Republic of Ireland. Pronounced effects of As toxicity in plants have been recognized in recent years especially from areas polluted by smelter waste and fallout. As-tolerant genotypes have developed during the past 100 years and may still be evolving at the present time.

Chromium uptake and transport in barley seedlings (Hordeum vulgare L.)

Potassium chromate is more toxic to the growth of barley in solution culture than chromic chloride, though apparent uptake of the latter is much faster. Inhibitor studies indicate that CrO4 (2-) uptake is "active" whereas Cr(3+) uptake is passive, demonstrating that the two forms do not share a common uptake mechanism. Studies on the form of Cr inside root cells show that in plants fed CrO4 (2-) the Cr remains largely unchanged whereas in plants fed Cr(3+) a little CrO4 (2-) (0.5 per cent) is produced. This conversion is dependent on the presence of living material and is probably enzymatic. Chromate uptake follows Michaelis-Menten kinetics at low concentration and is competitively inhibited by sulphate. Transport of chromium up the root is very slow, accounting for the low levels of Cr in the shoots. Chromate is transported better than Cr(3+) though still to a very limited extent. These experiments provide a physiological basis for previous observations.

The nature of uranium occurrence in the leaves of Coprosma australis (A. Rich.) Robinson

The distribution and chemical form of uranium was investigated in leaves collected from plants of C. australis (Rubiaceae) growing in a mineralized soil in the Buller Gorge, N.Z. Only small amounts of uranium � 10%) were found in a low molecular weight form. The predominant occurrence of uranium (65%) was as a uranium-RNA complex, which was isolated by high-voltage electrophoresis from an aqueous, extract of the freeze-dried leaves. Uranium (25%) was released from the solvent-extracted leaf residue by pepsin, thus revealing the presence of a uranium-protein complex. However, in view of the known dissociation constants for these two complexes, and other tests, it is clear that the majority of the uranium in vivo is in the form of a uranium-protein complex. This finding is confirmed by a differential centrifugation experiment, in which it was shown that at least 50% of the total uranium was bound to cell wall proteins.

The occurrence of selenocystathionine in Morinda reticulata Benth., a toxic seleniferous plant

Chronic selenosis in Australia has been described in horses and cattle (McCray and Hurwood 1963) from north-western Queensland and in horses (Knott, McCray, and Hall 1958) from the Cape York Peninsula. Ingestion of the seleniferous legume Neptunia amplexicaulis Domin. was implicated in the selenosis in the former instance and in earlier work from this laboratory Peterson and Butler (1967) isolated a seleno-amino acid which accounted for a considerable proportion of the selenium in the plant. The substance was characterized as selenocystathionine which had been shown by Aronow and Kerdel-Vegas (1965) to have pharmacological activity. However, N. amplexicaulis is apparently absent from the Cape York Peninsula, the selenosis being ascribed to ingestion of Morinda reticulata. The work reported in this paper was undertaken to identify the selenium-containing compound(s) in this latter plant species.

Chromium-51 distribution in tissues and extracts of Leptospermum scoparium

Leptospermum scoparium plants cultured in solutions containing Na2 (51)CrO4 accumulated most of the absorbed radioactivity in the roots. About one third of the root radioactivity was soluble in 80% ethanol in the form of three (51)Cr-complexes, the predominant one being identified as trioxalatochromate (III) ion. These complexes were also present in stem and leaf extracts. (51)Cr distribution was examined in various chemical fractions; protein and nucleic acids were especially low in radioactivity.

Uptake and Metabolism of Inorganic Forms of Selenium-75 by Spirodela Oligorrhiza

The duckweed Spirodela oligorrhiza was cultured at both pH 5 and 7�2 in sterile nutrient solutions containing 75Se-labelled selenite or selenate. At both pH values, selenite was absorbed and assimilated about three times more readily than selenate_ Colloidal selenium-75 at pH 7�2 was also investigated and found to be metabolized to a considerable extent. The labelling patterns observed were very similar for all three inorganic forms of selenium, with a predominance of selenomethionine incorporated into proteins.

The Uptake and Assimilation of Selenite by Higher Plants

Plants of wheat, ryegrass, red clover, white clover, and Neptunia amplexicaul'is (a selenium accumulator) were grown in nutrient solutions containing 75Se-selenite ion. The uptake of 75Se was measured and the root and shoot tissues fractionated to examine the products of selenite assimilation.