Browse

1 - 10 of 427 items :

  • Environmental Chemistry x
Clear All

Abstract

Acalypha wilkesiana is a tropical herb used for the treatment of skin disorders. Phytochemical studies carried out on the pulverized dried leaves of the plant revealed the presence of alkaloids, cardiac glycosides, anthraquinones, saponins, flavonoids and tannins. The crude 50% methanol extract obtained from the dried leaves was sequentially partitioned into three fractions. Thin layer chromatography of the fractions revealed three (3) components each in hexane fraction; ethyl acetate fraction and butanol fraction of the plant extract. Column chromatography of the fractions was carried out. The infrared analyses of the components revealed the presence of alkenes, hydroxyl group, conjugate carbonyls, esters in the hexane fraction components. Those from the ethyl acetate and butanol fractions contained aliphatic amides or amines with carbonyl and esters attached in the two fractions. Essential oil was extracted from the dried leaves using hydro-distillation method. GC-MS analysis of the essential oil revealed the presence of major compounds which included: n-Hexadecanoic acid 4-Hexen-2-one-3-methyl, Pyrrole and 6- Benzamido-4-benzoyl-1,2,4-triazine-3,5. The presence of the functional groups inferred from IR and GC-MS analyses with the antimicrobial potential of the essential oil may support the use of the plant in the management of skin infections, gastrointestinal disorders and other ailments.

Abstract

Malaria and toxoplasmosis are two important parasitic diseases with significant public health concerns in the Sub-Saharan African countries. Some aspects of pathogenesis of the two parasitic diseases involve the central nervous system manifesting neuropsychiatric disorders. Studies have implicated the single infection by Plasmodium spp. and Toxoplasma gondii in development of psychosis. Although concomitant infection of the two parasites suggests an aggravated psychotic condition, there is currently no reported study. This article reviewed some studies which implicated malaria and toxoplasmosis in psychosis. It further explored the likely role of concurrent infection by the parasites on psychosis, the dynamics of their pathology and possible effects of certain psychosis-associated cytokines and other biomolecules on the central nervous system. We recommend evidence-based research efforts in this field for the effective management of these two parasitic diseases to abate the public health burden of psychosis.

Abstract

As a result of the activity of industrial enterprises, atmospheric air is being contaminated by gaseous pollutants. Such substances as chlorine and hydrogen chloride are considered to be harmful for both humans and plants. Vegetation is a universal filter that is able to combat the environmental pollution by industrial emissions with the help of appropriate technical facilities. The aim of this study is to analyze the level of accumulation of chlorine in the leaves of woody plants that grow in the area of forest plantations of sanitary protection zones of industrial enterprises. The objects of the study were the species of woody plants in the area of protective plantations of a number of enterprises in Zaporizhzhya: ZTMC, ZALК, ZABR, Zaporizhstal, Zaporizhzhya Ferroalloy Plant, Zaporizhvohnetryv, Ukrgrafit and Zaporizhtransformator. We established that during the vegetation period, a gradual accumulation of the element was the most intense in mature leaves, whose growth had already ceased. The maximum amount of chlorine was found at the end of the vegetation period. The concentration of the pollutant in leaves of woody plants in the area of sanitary protection zones of industrial enterprises is linearly proportional to the level of emissions of the pollutant into the atmosphere by a given enterprise. The largest coefficient of relative accumulation of chlorine in the leaves of such plants as Catalpa bignonioides, Acer negundo, Robinia pseudoacacia, Juglans regia, Populus alba, which can be used as information sites for the purpose of bioindication of atmospheric air pollution with chlorides, was established.

Abstract

In the submitted paper, we have analysed the results of a systematic survey of grassland communities, performed in Hodrušská hornatina highland, in Štiavnické vrchy mountains. The main aims of the research were: i) syntaxonomical classification of grassland vegetation; ii) analysis of the main ecological gradients in species composition; iii) evaluation of the influence of environmental factors on species composition of grasslands. The dataset included 153 phytosociological relevés recorded on grasslands. Grassland communities were classified within five associations: Holcetum lanati, Pastinaco sativae-Arrhenatheretum elatioris, Alchemillo-Arrhenatheretum elatioris, Anthoxantho odorati-Agrostietum tenuis, Onobrychido viciifoliae-Brometum erecti; and the successional and transitional stages belonging to alliances Arrhenatherion elatioris and Bromion erecti. The results of the Detrended Correspondence Analysis support our assumption that the main environmental gradient in species composition on grassland is related to moisture. The results of the Redundancy Analysis show that all used environmental variables explained 3.4% of the variability of the species data. The most important factors affecting the species composition were altitude, slope, distance from settlements, and management.

Abstract

This study shows the impact of the reforestation program by some tree species (Pinus halepensis, Cupressus sempervirens and Eucalyptus camaldulensis) on the soil physicochemical parameters in south-western Algeria steppe. The study was realized on soil samples from the Touadjeur site. One hundred soil samples were taken from the field, followed by physicochemical analyses in the laboratory. A comparison of the soil elements between reforested and unreforested sites considered as a control was carried out. The results show that there are differences in the physicochemical parameters of the soil between the reforestation and the non-reforestation ones constituted by a steppe vegetation. The ANOVA one way test shows a highly significant difference change in soil physical parameters, moisture, holding capacity and saturated hydraulic conductivity, but no change in apparent density, actual density and color. Also, from a chemical point of view, the differences concern the organic matter, organic carbon, pH and certain soil contents. The main differences in soil properties between the reforestation sites and the control site, reflect the consequences of forest management adopted by the forest services, most probably the choice of reforestation species.

Abstract

The landscape of south-western Slovakia is characterised by anthropogenous reshaping, while fragments of undisturbed, waterlogged habitats have been preserved in what remains of the meandering ancient Žitava River. These refuges are inhabited by various small mammal species and their blood-sucking ectoparasites. Between 2014 and 2018, research on them was carried out in Slovakia’s Danubian Lowland (Podunajská nížina) during three out of the four seasons (spring, summer and autumn). The small mammals were captured at 27 localities. The occurrence of nine flee species from the Hystrichopsyllidae, Ctenophthalmidae and Ceratophyllidae families was documented on 12 small burrowing mammals. During the course of all the seasons in which research was conducted, Ctenophthalmus agyrtes, C. assimilis, Megabothris turbidus a Nosopsyllus fasciatus were found, among the most dominant species to be seen on small burrowing mammals.

Abstract

An ecosystem engineer is a species that indirectly changes the availability of resources for other organisms via physical modification of the habitat. A good example of such species is Ardea cinerea L. – a big waterbird that forms colonies up to a few hundreds of nests during the breeding season. The colonies modify the habitat in the close vicinity of the nests mainly through heavy input of organic matter (feces, dropped or regurgitated food leftovers, eggshells, dead birds, etc.), which in turn affects vegetation. In our previous study, we observed that the probability of occurrence of non-forest species under the nests was 29.5 times higher in control plots in two types of forest vegetation (oligotrophic pine forest and riparian mixed forest). Adaptation for long-distance dispersal turned out to be insignificant for the probability of species occurrence, which suggested that the diaspores of those species must have been present in the forest soil before the establishment of the grey heron colony. In the present study, we used the seedling emergence method to compare the structure of the soil seed bank in breeding sites and control plots in two forest ecosystems mentioned above. We also tested whether the increased amount of nitrates in soil had a positive effect on the rate of germination and growth of seedlings. The results have shown that some reservoir of ruderal species was indeed present in the control plots, although their amount was higher under the heronries. We have proved that the number of germinating seeds of ruderal species depends on the concentration of nitrate in the soil of the pine forest. Comparison of the dry weight of 30- and 60-day-old seedlings of Rumex acetosella (pine forest) and Betula pendula (riparian forest) from the control and breeding sites showed an increased size of seedlings coming from the breeding sites of both forest communities.

Abstract

Biodiversity increases the stability of ecosystem functioning. This is the most frequent pattern in the field of ecosystem functioning, which has been evaluated generally at the community scale. However, most management decisions are made at the landscape scale, which requires the need to confirm these relationships at this level. In the study, we analyzed the relationship between temporal variability of ecosystem functioning and two landscape diversity indices (Shannon and Pielou). We used snow water equivalent and soil moisture content as the indicators of functioning, which are closely related to the runoff formation function. The field data were collected in a small plain basin of the Kasmala river during the period from 2011 to 2017. Within four spatial scales, we have not identified significant linear relationships between the indicators of functioning and diversity indices. These results indicated the strong influence on the total variability by variation in the most widespread ecosystem types (also called idiosyncratic response). It is one of the consequences of landscape structure homogenization within the study area.

Abstract

Soil carbon sequestration plays an important role in mitigating the anthropogenic increases in atmospheric carbon dioxide concentrations. Pastures and meadows are the significant localities for the deposition of soil organic carbon (SOC). The objective was the comparison of the impact of plant species and their quality on the deposition of SOC under the grasslands in 18 variants of meadows and pastures at the original unfertilized soils, the overfertilized soils by organic fertilizers in the form of excrements and the soils after the ecological regeneration by regrassing. The plots 5, 8, 9 and 10 were used on a long-term basis as old semi-natural sheep pastures from the 15 century. We took into consideration the deposits of SOC and Nt in soil. The old semi-natural pasture proved the most intensive transformation and accumulation of SOC (even 5.60%) and the highest values were measured in the depth I (0–100 mm) soil layer, the concentrations decreased along with the depth in all treatments. At these plots, there was the lowest yield of dry matter and quality (EGQ). The yield of dry matter in t.ha−1, the number of species, EGQ and C:N in the depth I with the significant impact on the species variability, which were selected by Monte-Carlo permutation test explain up to 47% of the total variability. According to the result of “forward selection” in RDA analysis, out of all significant factors, the number of species has the biggest impact on the total species variability, which represents 17% of the total variability. The total evaluation indicates that from the agricultural aspect of utilization, a more favourable quite high content of SOC was deposited at the ecologically regenerated grasslands by the additional sowing of the valuable autochthonous plant species.