A novel multi-model data-driven ensemble approach for the prediction of particulate matter concentration

Environmental Science and Pollution Research - Accuracy in the prediction of the particulate matter (PM2.5 and PM10) concentration in the atmosphere is essential for both its monitoring and...     

Prenatal exclusion of X-linked hydrocephalus-stenosis of the aqueduct of sylvius sequence using closely linked DNA markers

X-linked hydrocephalus-stenosis of the aqueduct of Sylvius sequence (H-SAS, MIM number 307 000) is a rare genetic disorder characterized by hydrocephalus, macrocephaly, adducted thumbs, spasticity, mental retardation, and cerebral malformations. This regularly lethal condition is usually diagnosed at birth or prenatally by ultrasound, but hydrocephalus may be moderate or even undetectable on fetal ultrasound examination. Moreover, since heterozygous women are asymptomatic, carrier detection is at present impossible before the birth of an affected son. Therefore, mapping the H-SAS locus to distal Xq (Xq28) was of primary importance for genetic counselling and prenatal diagnosis. Here, we report prenatal exclusion of H-SAS with a probability of 97.6 per cent in two male fetuses with a 50 per cent a priori risk of being affected using closely linked Xq28 DNA markers.     

A new C12 alcohol identified as a sex pheromone and a trail-following pheromone in termites: the diene (<Emphasis Type="Italic">Z</Emphasis>,<Emphasis Type="Italic">Z</Emphasis>)-dodeca-3,6-dien-1-ol

The diunsaturated C12 alcohol (Z,Z)-dodeca-3,6-dien-1-ol (dodecadienol) has been characterized by GC-MS and FTIR as a novel releaser pheromone in termites. This alcohol identified in Ancistrotermes pakistanicus (Termitidae, Macrotermitinae) possesses a double pheromonal function which again illustrates the chemical parsimony of termites compared with other social insects. In workers, dodecadienol elicits trail-following at a very low concentration (activity threshold at 0.1 pg/cm of trail); in male alates it induces trail-following at a low concentration (1–10 pg/cm) and sexual attraction at a higher concentration (about 1 ng). Traces of the monounsaturated C12 alcohol (Z)-dodec-3-en-1-ol (dodecenol), known as a trail pheromone of several Macrotermitinae, were also found in the sternal gland extracts of A. pakistanicus, although only dodecadienol was present at the surface of the sternal gland. Workers of A. pakistanicus are not sensitive to dodecenol, but they are as sensitive to dodecatrienol as to dodecadienol. However, in the study area (Vietnam), A. pakistanicus is living in sympatry only with those Macrotermitinae using dodecenol as a trail pheromone, the foraging populations therefore being well isolated through their respective trail pheromones. The presence of three types of unsaturated C12 alcohols as releaser pheromones in the only Macrotermitinae subfamily is discussed, and a possible biosynthetic pathway from linoleic acid is proposed for dodecadienol.     

Prospective maternal serum human chorionic gonadotropin screening for the risk of fetal chromosome anomalies and of subsequent fetal and neonatal deaths

A prospective study of maternal serum human chorionic gonadotrophin (hCG) measurement for the selection of pregnancies with an increased risk of fetal trisomy 21 was undertaken in 24 000 pregnancies from 1 January 1989 to 31 December 1990. Maternal serum was sampled at 15-18 weeks of gestation. hCG was measured in one laboratory, with one technique. This ‘hCG high level’ technique was developed for this screening. Amniocentesis was offered to each woman with a maternal serum hCG level above the cut-off. The follow-up of the pregnancies is known in 92 per cent of cases. The combination of hCG values and maternal age gave a detection efficiency of 63 per cent for trisomy 21 with rates of amniocentesis of 30 per cent for patients aged 37 years, 20 per cent for patients aged 35 or 36 years, and 5 per cent for patients under 35 years of age. Based on this prospective study, an individual risk was calculated combining the serum hCG value and maternal age. Seventy-four per cent of trisomy 13, trisomy 18, triploidy, and 5p- deletion were detected either in the same selected group of women or in combination with ultrasonography performed when hCG values were very low. The follow-up study showed that women who had high or low hCG values represented a group at high risk for fetal or perinatal death.     

Vertical structure of very nearshore larval fish assemblages in a temperate rocky coast

Small-scale vertical patterns of larval distribution were studied at a very nearshore larval fish assemblage, during the spring–summer period of several years, at two depth strata (surface and bottom) using sub-surface and bottom trawls. A total of 4,589 larvae (2,016 from surface samples and 2,573 from bottom samples) belonging to 62 taxa included in 22 families were collected. Most larvae belonged to coastal species. Although inter-annual variations in larval density and diversity could be found, total larval abundance was always higher near the bottom whereas diversity was higher at the surface. A marked distinction between the structure of surface and bottom assemblages was found. Sixteen taxa explained 95% of the similarity among surface samples. Larvae which contributed most to this similarity included species like clupeiformes, sparids and serranids, and also blenniids, tripterygiids and some labrids. In the bottom samples, fewer species were present, with only six taxa, almost exclusively from species which lay demersal eggs, contributing to 95% of the similarity between samples. Larvae present at the surface were significantly smaller than at the bottom. For some of the most abundant species found at the bottom, only small larvae occurred at the surface while the whole range of sizes was present at the bottom, indicating that larvae may be completing the entire pelagic phase near the adults’ habitat. These results indicate that larval retention near the reefs probably occurs for these species, although for others dispersal seems to be the prevailing mechanism.     

Karyology of the toadfish Porichthys plectrodon (Jordan and Gilbert, 1882) (Batrachoididae) from Margarita Island,Venezuela

This paper reports the results of cytogenetic analyses carried out on Porichthys plectrodon using conventional Giemsa staining, C-banding and silver staining techniques. A diploid chromosome count of 2n=44 was observed, consisting of 8 metacentric, 10 submetacentric, 6 subtelocentric and 20 acrocentric chromosomes. Differences in length made it possible to identify homologous chromosomes within the metacentric group. Constitutive heterochromatin was distributed as large pericentromeric blocks in pairs 1 and 2, while the rest of the chromosomes were marked in centromeric regions, some more conspicuously than others. One pair of small-sized acrocentric NOR-bearing chromosomes (21) was identified by the nucleolar regions located terminally on their short arms.Communicated by P.W. Sammarco, Chauvin     

Application of rough sets analysis to identify polluted aquatic sites based on a battery of biomarkers: a comparison with classical methods

The evaluation of toxicological effects at the cellular and molecular levels in organisms are often used to determine sites subjected to contamination problems that pose a threat to the long-term survival of organisms. However, the integration of multiple measurements on the health status of organisms into a model for site discrimination is challenging. This study compares two discrimination methods which are based on rule inference: rough sets (RS) analysis and classification trees (CT) with classical multivariate discriminant analysis (DA). Site classification was attempted with six biomarkers of effects: metallothionein levels, lipid peroxidation, DNA damage, levels of lipophosphoproteins (i.e., vitellins), phagocytosis activity and haemocyte cell viability on clam (Mya arenaria) populations from the Saguenay River fjord (Quebec, Canada). Rule based methods have the advantage of complete independence from data distribution constraints in contrast to the classification methods from multivariate analysis that are more commonly used in ecotoxicology. Results show that RS and CT gave better classifications than DA because they do not require strong distributional assumptions. Moreover, RS provided classification rules that could identify the most important biomarker(s) for site discrimination. RS and CT were shown to be simple and efficient methods for classifying multivariable ecotoxicological data. This methodology would be especially useful when freedom from distributional assumptions is required.     

Phytoremediation of petroleum hydrocarbons in tropical coastal soils II. microbial response to plant roots and contaminant

GOAL, SCOPE AND BACKGROUND: The goal of this study was to understand the interaction between plants and microorganisms during petroleum-hydrocarbon bioremediation in Pacific Islands coastal soils. Total bacteria and hydrocarbon-degrading microorganisms population dyanamics were examined in the rhizospheres of tropical trees and shrubs, which were evaluated for their phytoremediation potential in a greenhouse experiment. The respective and combined effects of plant roots and diesel contaminant on the microbial populations were determined in relation to diesel fuel depletion. An increase in the grading populations size of the hydrocarbon-degrading populations of microbes, elicited by rhizodeposition, is generally regarded as conducive to an enhanced degradation of petroleum hydrocarbon pollutants in vegetated soil. METHODS: The soil was a coastal sandy loam (pH 7.8) which was artificially contaminated with 10 g of No. 2 diesel fuel/kg soil or left uncontaminated. The pots were irrigated with fertilizer and 1% NaCl. The enumerations were carried out in the contaminated and uncontaminated rhizospheres of three trees, kiawe (Prosopis pallida), milo (Thespesia populnea), and kou (Cordia subcordata) and three shrubs, beach naupaka (Scaevola sericea), false sandalwood (Myoporum sandwicense), and oleander (Nerium oleander). Unplanted control soils were included in the experiment. Total bacteria and phenanthrene-degrading bacteria were enumerated on plates. Diesel- and pristane-degrading microorganisms were enumerated by the most-probable-number technique in tissue-culture plates. RESULTS AND DISCUSSION: All four types of microorganisms responded to the rhizosphere of the 6 plants in uncontaminated soil and to the diesel contaminant in unplanted soil. In contaminated rhizospheres, no effect of the plant on the hydrocarbon-degrader numbers was visible. Total bacteria responded more to the plant roots than to the contaminant. The phenanthrene-degrading bacteria and pristane-degrading microorganisms were more influenced by the contaminant than by the plants. The diesel-degrading microorganisms were equally stimulated by the plants and the contaminant. The numbers of hydrocarbon degraders were similar in the contaminated rhizospheres of the three effective plants (kiawe, kou, and milo) and in those of the three ineffective shrubs. CONCLUSION: The results suggest the quality of the rhizodeposition is plant-dependent and governs the type of diesel-degrader populations that will be enhanced by a given plant. RECOMMENDATIONS AND OUTLOOK: In the proposed phytoremediation-benefit model plant roots maintain high levels of hydrocaron degraders in uncontaminated soil. When the root enters a contaminated zone of soil, those hydrocarbon degraders that prefer the contaminant would switch to the contaminant as a carbon source, effectively removing the hydrocarbons. If the root exudates and the contaminant are equally attractive to the hydrocarbon degraders, the contaminant degradaton would be less effective.     

Analytical methods for the determination of alachlor, metolachlor, simazine and atrazine mobility in soils

A method for the determination of the mobility of the herbicides, alachlor, metolachlor, simazine and atrazine in soil is described. The method is based on the use of soil thin-layer chromatography (TLC) and does not require the use of radiolabelled compounds. Soil on the TLC plate after development was separated into various bands, the material in each band was extracted with solvents and analyzed by gas chromatography.     

14C-dimethoate residues in olive oil during oil processing

An olive tree was treated twice in the field with 14C-dimethoate (237.7 muCi, 2.4 g) and 14C residues were determined in the olive fruits at harvest. The fruits were crushed and pressed to extract the crude oil, then refined by neutralization, bleaching and deodorization. The crude oil contained 14.1% of the total 14C in the olive fruits. Neutralization resulted in a reduction of 14C by about 50% of the total 14C residues in oil. Bleaching and deodorization processes further reduced the 14C residues and the refined oil contained 31.6% (which corresponds to 4.4% of 14C residues of the total 14C in olive fruits) of the total 14C in the crude oil. Industrially extracted crude oil was fortified with 14C-dimethoate at 1.8 mg kg-1 (0.02 muCi) level and subjected to the same refining process. A sharp decrease in the amount of 14C was observed by neutralization and the amount of 14C remaining in the refined oil was about 7.3% of the total 14C in the crude fortified oil. The data suggest that the 14C residues in the aged and the fortified oil amples were not of the same nature. The terminal 14C residue in the refined oil obtained from the field experiment did not contain dimethoate and/or its oxon.