Mechanism of chiral recognition in the enantioseparation of 2-aryloxypropionic acids on new brush-type chiral stationary phases

New brush-type chiral stationary phases (CSP I-IV) comprising N-3,5,6-trichloro-2,4-dicyanophenyl-L-alpha-amino acids (1-4) were prepared by binding of chiral selectors 1-4 to gamma-aminopropyl silica gel. To check the role of excess free aminopropyl groups, CSP V was prepared by binding N-3,5,6-trichloro-2,4-dicyanophenyl-L-alanyl-(3-triethoxysilyl)propylamide to unmodified silica gel. The best separation of racemic 2-aryloxypropionic acids (TR-1-13) was obtained with CSP I; the -(-)-S enantiomer were regularly eluted first, as determined by a CD detector. The mechanism of chiral recognition implies a synergistic interaction of carboxylic acid analyte with the chiral selector and achiral free gamma-aminopropyl units on silica. In fact, CSP V, which is lacking an achiral aminopropyl spacer, shows a lower separation ability for 2-aryloxypropionic acids, but a similar enantioselective discrimination of esters TR-19-20, in comparison with CSP I. CSP I-IV retain unaltered separation ability after a few months of continuous work using a large number of various mobile phases.

Airborne coagulase negative staphylococci produced by a sewage treatment plant

Since some coagulase-negative staphylococci species are involved in clinical and environmental situations, the authors carried out a study on the spread of these bacteria in the air of a sewage treatment plant. For these purposes a total of 196 samples were taken from 16 sampling stations, 11 during the day and 5 at night (only at 4 points), using the settle plate technique. Altogether 13 species of coagulase negative staphylococci were isolated: S. haemolyticus, S. xylosus and S. cohnii were particularly common. Station no. 2 (an area almost always kept closed containing the fine screens) was found to be the most contaminated. The presence of coagulase negative staphylococci was favoured by high temperatures and low humidity. No differences were found due to variations in wind speed and direction or between day and night.

Evaluation of the efficiency of peracetic acid in the disinfection of sewage effluents

AIMS

Evaluation of the efficiency of peracetic acid in the disinfection of wastewater in a large treatment plant.

METHODS AND RESULTS

Over a period of 18 months 30 sample collections were made, each consisting of three samples taken from: raw incoming sewage, secondary effluent (after 10-12 h) and secondary effluent disinfected with 1.5-2 mg l(-1) of peracetic acid (contact time: 20 min). Total coliforms and Escherichia coli declined from 10(7) MPN 100 ml(-1) in the raw sewage to 10(2) in the disinfected effluent and the enterococci fell from 10(6) MPN 100 ml(-1) to 702 MPN 100 ml(-1). The reduction of bacteria increased with the rise in temperature and decreased with the rise in BOD5.

CONCLUSIONS

Disinfection with peracetic acid reduced levels of faecal contamination by 97%, thus attaining the limit recommended by current Italian law (Escherichia coli <or= 5000 MPN 100 ml(-1)) for discharge into surface waters.

SIGNIFICANCE AND IMPACT OF THE STUDY

The process of disinfection with peracetic acid is easier to manage than other more common methods and the tests performed confirm that from the bacteriological point of view good results can be obtained for urban effluents.

Biological and molecular characterization of a pigeon paramyxovirus type-1 isolate found in Argentina

In this report, we describe the biological and molecular characterization of a paramyxovirus type-1 (PPMV-1) isolate found in wild pigeons in an urban habitat in Buenos Aires, Argentina. Of the nine pigeons captured, three were moribund, and the other six showed diarrhea, ataxia, tremor, torticolis, and wing paralysis. The intracerebral pathogenicity index was 1.29, and the amino acid (aa) sequence at the fusion protein cleavage site was 112GRQ KRF117. These characteristics correspond to a virulent Newcastle disease virus isolate. Nevertheless, it was not possible to reproduce the disease in chickens experimentally although the chickens exhibited seroconversion after inoculation. On the other hand, pigeons inoculated with the isolate became sick. These results provide further evidence about the unusual pathogenicity of PPMV-1 for chickens and show once more the need for more biological determinations in these cases to arrive at a final conclusion.

gamma-Linolenic acid production by solid-state fermentation of Mucorales strains on cereals

Oleaginous fungi of the genus Mucorales were screened for gamma-linolenic acid (GLA) production on solid substrates containing moistened cereals. Cunninghamella elegans CCF 1318 produced the highest yields of GLA when cultivated on barley. Substrate moisture and cultivation temperature proved critical for effective GLA production. Vegetable oil supplied to the cultures improved GLA production. Rotating bottles and plastic bags were used as cultivation vessels to reproduce the conditions found in rotating drums and tray bioreactors, respectively. After 11 days of cultivation at 21 degrees C, C. elegans produced 14.2 mg of GLA per gram of dry substrate, composed of a mixture of barley, spent malt grains (SMG) and peanut oil. GLA represented 15.6% of the total fatty acids in the lipid extract.

Tobacco smoking among high school students in Romagna (Italy) and evaluation of a prevention campaign

The aim of this study was to investigate the smoking habits of a sample of second year high school students in Romagna (Northern Italy) by means of an anonymous self-administered questionnaire and the efficiency of a previous health education campaign. A sample of 2,691 16-year-old pupils (74% of the school population of this age) was randomly selected. Of these, 863 (32.1%) had participated in a prevention campaign while attending middle school. 19.1% of the students who had taken part in the campaign were smokers compared to 23.2% of those who had not. The students' smoking habits were found to be influenced by the type of school and by the role models (parents, siblings, friends, teachers). The campaign appears to have had good results, especially in places where it was carried out on a wide scale. Suggestions are made for making such campaigns more efficient.

Recovery of Burkholderia pseudomallei and B. cepacia from drinking water

Samples of drinking water were examined in order to evaluate the occurrence of two gram-negative bacteria: Burkholderia pseudomallei and B. cepacia. A total of 85 samples were collected from public and private buildings in the province of Bologna (Italy). Other bacteriological indicators (heterotrophic plate count at 22 and 36 degrees C) were also examined, together with physical and chemical parameters (temperature, pH, residual chlorine, total hardness and chemical oxygen demand (COD)). High levels of B. pseudomallei were recovered (mean value = 578 cfu/100 ml) in about 7% of samples, while B. cepacia was recovered in 3.5% (mean value = < 1) of the samples. The two microorganisms were found to correlate positively with heterotrophic plate counts at 22 and 36 degrees C, but not with the physical and chemical parameters taken into consideration.

Water characteristics associated with the occurrence of Legionella pneumophila in dental units

This study evaluated the incidence of Legionella pneumophila in dental unit water samples and investigated how the occurrence of these bacteria may be related to some physical, chemical and bacteriological characteristics of the water. The samples were taken from the incoming tap water, oral rinsing cup, air-water syringe, ultrasonic scaler, and the turbine of 23 dental units of private and public institutions. Apart from L. pneumophila (serogroup 1 and 3) isolated in 22 out of the 101 (21.8%) water samples tested, two other species were found: L. bozemanii and L. dumoffii. The highest densities and frequency of L. pneumophila were observed in the water coming into the units and in the dental units of public institutions. A negative association between L. pneumophila and 36 degrees C and 22 degrees C heterotrophic total plate counts and other gram-negative bacteria was found. An inverse association between the concentration of L. pneumophila and water temperature was also observed. The values of pH and total hardness did not show any significant difference in the L. pneumophila-positive and -negative dental unit waters. Finally, the chemical oxygen demand (COD) and residual chlorine were found to correlate positively with L. pneumophila.

Occurrence and seasonal variation of airborne gram negative bacteria in a sewage treatment plant

A study was carried out to determine the microbial density and the seasonal variation of airborne Gram negative bacteria in a sewage treatment plant. Sampling was made at 16 sites and the settle plate technique was used. Of the 201 samples examined, 43.2% revealed fecal coliforms (mean value = 14 cfu/p/h), 53% Pseudomonas spp. (mean value = 11 cfu/p/h), 46.5% Shigella spp. (mean value = 13 cfu/p/h), 3% Legionella spp. (mean value = 2 cfu/p/h) and 2% Salmonella (mean value = < 1 cfu/p/h). 72% of the samples contained "other" Gram negative bacteria such as Aeromonas hydrophila, Serratia marcescens, Enterobacter cloacae and others. With the exception of Legionella spp. and Salmonella, all other bacteria were more frequent and numerous in the October-March period, when temperatures were lower and humidity higher. Although the oxidation tanks were covered overall contamination was nevertheless high, thus presenting a potential health risk for plant workers.

Striatum adenosine A2 receptors are modified during seizure: effect of cyclopentyladenosine administration

Rat CNS adenosine A2A receptors were studied after administration of the convulsant drug 3-mercaptopropionic acid (MP) and the adenosine analogue cyclopentyladenosine (CPA) by means of a quantitative autoradiographic method. Specific binding was quantified in striatum only. The highest density was found in caudate-putamen (2.50 fmol/mm2), followed by nuclei accumbens (1.85 fmol/mm2) and the lowest values in the olfactory tubercle (1.26 fmol/mm2). These differences were statistically significant. MP administration (150 mg/kg) caused significant increases (12-18%) in caudate-putamen and nuclei accumbens in both stages: seizure and postseizure and no changes in the olfactory tubercle. CPA administration (2 mg/kg) originated a rise of 16% in nuclei accumbens but no change in the other two regions. When CPA was injected 30 minutes before MP, an increase (18 to 45%) in caudate-putamen and nuclei accumbens at seizure and postseizure stages was observed. Saturation results, in striatal membrane fraction, indicate that receptor sites increased their maximal binding capacity (Bmax) while the apparent dissociation constant (Kd) remained unchanged. These results suggest the involvement of the adenosine A2A receptors in convulsant activity and that CPA administration at the dose selected brings about a rise in neuronal excitability in this area.

Newcastle disease virus surveillance in Argentina: use of reverse transcription-polymerase chain reaction and sequencing for molecular typification

Newcastle disease virus (NDV) remains a major pathogen of poultry where highly virulent strains require reporting to the Office of International Epizootes. NDV is a paramyxovirus existing as different strains classified on the basis of severity of the disease they cause. The present study was conducted in Argentina to determine the prevalence of highly virulent velogenic NDV strains in commercial poultry farms. Tracheal and cloacal swabs from 693 flocks, representing 14% of the broiler production, were collected and pooled. A pool amplified twice in embryonated eggs presented a limited hemagglutination titer. We performed reverse transcription coupled to polymerase chain reaction to amplify fusion and matrix protein gene sequences of the isolate and the strain Trenque Lauquen, isolated in Argentina during an outbreak in 1970-71 and previously characterized as velogenic viscerotropic by biological methods. The amino acid sequences were deduced from nucleotide sequences of the amplification products and the pathotype predicted according to the sequences obtained. From the samples analyzed, we found only one type of NDV, being the isolate identified as lentogenic NDV. This strain is probably the one used in vaccination of flocks where that sample was obtained. These data have allowed us to consider a velogenic NDV-free status in Argentina's commercial poultry.

Effect of heat and acid decontamination treatments on the recovery of Legionella pneumophila from drinking water using two selective media

Two different decontamination systems, heat and acid, and two isolation media, GVPC and MWY agar were tested for the recovery of Legionella pneumophila from drinking water. The samples were concentrated by filtration through 0.2 micron polyamide filter and the membranes were resuspended in the original water samples. The suspension was divided into three parts: the first was placed in a 50 degrees C water bath, the second was acidified in HCl-KCl solution and the third did not undergo any treatment. The isolation was made by means of media containing charcoal, yeast extract and glycine with cycloeximide (GVPC) or vancomycin, polimixin B, anysomicin and dyes (MWY). Heating at 50 degrees C for 30 minutes was seen to be the best decontamination system above all when used with GVPC agar. Moreover, with this pretreatment higher counts were obtained both on MWY and GVPC agar. The MWY agar produced the highest isolatin percentages and the highest counts.

Comamonas acidovorans contamination of dental unit waters

A study was carried out to evaluate the extent of the colonization of dental water systems by Comamonas acidovorans and to investigate how the occurrence of these bacteria is related to certain water characteristics. The 152 water samples were collected from the oral rinsing cup, air-water syringe, turbine and supply lines to dental units. Comamonas acidovorans was found most frequently and in greatest quantities in samples taken from water entering the units and in samples with a lower total bacterial count at 22 degrees C, higher temperature, lower content of organic matter and, in general, higher concentrations of residual chlorine.

Occurrence, removal and seasonal variation of thermophilic campylobacters and Arcobacter in sewage sludge

The presence of thermophilic campylobacters and Arcobacter was investigated in four types of sewage sludge taken from the treatment plant in Bologna (Italy): primary, activated, thickened and anaerobically digested sludge. Campylobacter jejuni and Campylobacter coli were more numerous during the March-September period and were found only in primary sludge (22.7%) with mean counts of 278 MPN/g dry matter and 1403 MPN/g dry matter respectively. Arcobacter butzleri were found in all types of sludge with frequencies of 80% in activated and thickened sludges and 41% in digested sludges. They were more numerous in the spring/summer period with peaks in April, May, June and September. They were less sensitive to anerobic digestion than fecal bacteria, probably due to their microaerophilic growth properties. However, since they are found in anaerobically digested sludges at mean values of 7649 MPN/g dry matter the land application of digested sludges may cause high risks infection.

Relationship between low lead exposure and somatic growth in adolescents

The possible effects of moderate lead exposure on human growth and development are not well defined. This study was carried out in order to evaluate the relationship between somatic growth and lead exposure. 418 subjects (202 males and 216 females) aged 11-13 years in good health and living in an area of the northern region of Italy were submitted to the following determinations: blood lead levels (PbB), serum concentrations of gonadotropins (LH, FSH) and sex-steroid hormones (DHA-S, T, E2) and anthropometric measurements (stature and weight). The mean blood levels were 85.39 and 70.08 micrograms/1, respectively, for males and females. Significant and negative relationships were found between blood lead levels and stature in 13 years old males and 12 years old females (p = 0.009 and p = 0.006, respectively). Negative relationships between lead in blood and LH and FSH were found only in males with lead levels higher than 90 micrograms/1. Our findings seem to suggest that even for low lead exposure this metal may affect stature growth and gonadotropins levels.

Occurrence of Listeria monocytogenes in sewage sludge

The search for salmonella is the only bacteriological index included in Italian guidelines (in accordance with EU regulations) for the use of sewage sludge in agriculture. As a result, information regarding the presence of Listeria monocytogenes is rather limited. We therefore decided to carry out an investigation of Listeria in the sludge produced by the Bologna (Italy) treatment plant during the various phases of treatment. Five different types of sludge were analysed (primary raw, activated, thickened, digested and dewatered) in a total of 66 samples. The highest frequency and concentrations of Listeria species (100% and 2,743 MPN/g dry matter) and the lowest (63% and 6 MPN/g dry matter) were found in the activated and digested sludge respectively. These bacteria were mostly present in spring and autumn and positively correlated only with fecal streptococci. Four species were isolated: Listeria monocytogenes, Listeria innocua, Listeria welshimeri and Listeria grayi. Listeria monocytogenes (prevalent serotype 4b) was seen to be resistent to the biological oxidation but sensitive to anaerobic conditions during thickening and digestion. The dewatering process led to an increase in contamination. Since the sludge is used to fertilize land destined for vegetable farming our results show that it may represent a potential health risk.

CNS adenosine A1 receptors are altered after the administration of convulsant 3-mercaptopropionic acid and cyclopentyladenosine: an autoradiographic study

Rat CNS adenosine A1 receptors were studied by quantitative autoradiography after the administration of convulsant 3-mercaptopropionic acid (MP) and an adenosine analogue cyclopentyladenosine (CPA), using 2-chloro-N6-[cyclopentyl-2,3,4,5-3H adenosine]-([3H]CCPA) as radioactive ligand. Specific binding was quantified in hippocampus, cerebellum, cerebral cortex, thalamic nuclei, superior colliculus and striatum, and the highest densities were found in CA1, CA2, and CA3 hippocampus subareas and the lowest levels in superior colliculus and striatum. MP administration (150 mg/kg, i.p.) produced significant increases in [3H]CCPA binding in CA1 subarea at seizure (15%) and postseizure (21%) and in CA2 at seizure (15%) but a tendency to decrease in dentate gyrus. There was an increase in cerebellum at seizure (18%) but no significant changes in the other studied regions. CPA injection (2 mg/kg, i.p.) enhanced [3H]CCPA binding in CA1 and CA2 areas (17-18%) but not in CA3 area of the hippocampus. When CPA was administered before MP, which delayed seizure onset, an increase in [3H]CCPA binding in CA1 hippocampus subarea (19%) and cerebellum (28%) was also observed. Results showed that the administration of convulsant MP and adenosine analogue CPA exerts differential effects on adenosine A1 receptors in CNS areas; hippocampus is the most affected area with all treatments, specially CA1 subarea, supporting an essential role in convulsant activity as well as in seizure prevention.

Smoking habits, exposure to passive smoking and attitudes to a non-smoking policy among hospital staff

A survey was carried out into the smoking habits and exposure to passive smoking among health staff in the hospitals of Faenza, Forli and Rimini (Emilia-Romagna, Northern Italy), 2453 subjects answered anonymously a 41 question questionnaire. 53% of the subjects were professionals nurses, 16% doctors, 15% maintenance staff, 10% ancillary staff, 1% non-medical graduates, 2% were administrators and 3% were assigned to the category ¿other'. Of the subjects answering the questionnaire 39% were smokers, 19% ex-smokers and 42% non smokers. The highest number of smokers was found among women (41%) compared to men (37%) and among ancillary staff (48%) compared to nurses (41%) and doctors (31%). The males were mostly heavy smokers (> or = 20 cigarettes/d) and smoked strong cigarettes (> or = 12 mg/cig condensate content). The females were mostly light smokers (< 10 cigarettes/d) and smoked light cigarettes (1-6 mg/cig condensate content). A high percentage of subjects (87%) smoked at work especially in areas reserved for staff. 43% and 26% of shift workers and non-shift workers tended not to modify their habit when on morning or afternoon shifts. During night shifts the majority of them increased their tobacco consumption. Around 87% of hospital employees stated they were exposed to passive smoking inside the hospital especially in cooking areas, at information desks and corridors. Nurses, ancillaries and maintenance staff were those most exposed and for a greater number of hours per day compared to doctors. Almost all subjects were aware of the harm caused by passive smoking. 56% of smokers, 65% of ex-smokers and 72% of non smokers said they were willing to participate in future campaigns to limit smoking in their hospitals.

Characteristics of non-O1 Vibrio cholerae isolated from the effluents of a treatment plant

We report the results of a study concerning the characteristics of 19 Non-O1 Vibrio cholerae strains isolated from the incoming sewage and the effluents of the treatment plant in Bologna (Italy). These strains were compared to those of a strain of Vibrio cholerae biotype El Tor. The behaviour of the Non-O1 Vibrios was seen to be quite similar to those of the El Tor biotype in all aspects studied and antigenic correlations were found by means of immunoblotting and cytotoxin production on VERO cells. Since these bacterial strains may be pathogenic in humans, we believe it useful to describe some of their characteristics.