Herbicidal activity of slow-release herbicide formulations in wheat stands infested by weeds

The present study reports the herbicidal activity of metribuzin and tribenuron-methyl embedded in the degradable matrix of natural poly-3-hydroxybutyrate [P(3HB)/MET and P(3HB)/TBM]. The developed formulations were constructed as films and microgranules, which were tested against the weeds such as white sweet clover Melilotus albus and lamb's quarters Chenopodium album in the presence of soft spring wheat (Triticum aestivum, cv. Altaiskaya 70) as the subject crop for investigation. The activity was measured in laboratory scale experiments by determining the density and weight of the vegetative organs of weeds. The study was also aimed at testing the effect of the experimental formulation on the growth of wheat crop as dependent on the method of herbicide delivery. The experimental MET and TBM formulations showed pronounced herbicidal activity against the weed species used in the study. The effectiveness of the experimental formulations in inhibiting weed growth was comparable to and, sometimes, higher than that of the commercial formulations (positive control). The amount of the biomass of the wheat treated with the experimental herbicide formulations was significantly greater than that of the wheat treated with commercial formulations.     

Effect of alkyl hydroxybenzenes on the properties of dioxygenases

The aim of the present work was to investigate the influence of alkylhydroxybenzenes (AHBs) and tyrosol, which belong to cell differentiation factors d(1) group of autoregulators on properties of biodegradation enzymes, catechol 1,2-dioxygenase (Cat 1,2-DO) and methylcatechol 1,2-dioxygenase (MCat 1,2-DO) of Rhodococcus opacus 6a. AHBs were found to have a greater effect on MCat 1,2-DO than on Cat 1,2-DO. It was expressed by more pronounced changes in the activity of MCat 1,2-DO with unsubstituted catechol at different AHB concentrations and by increasing thermostability of MCat 1,2-DO compared to Cat 1,2-DO under the protective action of AHBs. The compound C(7)-AHB shifted the maximum of dioxygenase activities towards higher temperatures and increased their operation optimum. AHBs changed the specificity constant of dioxygenases by decreasing/increasing the K(m)/V(max) value. For example, the increase in the V(max) value of 3,6-dichlorocatechol oxidation by Cat 1,2-DO in the presence of C(7)-AHB was 300-fold higher compared to the same reaction without AHB. The influence of cell differentiation factors on the properties of dimeric enzymes has been shown for the first time. It gives an idea of how the specificity of enzymes can be changed in vivo when strains contact new substrates. The work has shown the possibility of modification of the properties of dimeric enzymes towards the extension of enzyme activity with difficulty converted substrates or in more extreme conditions, which may be important for biotechnological processes.     

Effervescence assisted dispersive liquid–liquid microextraction followed by microvolume UV-Vis spectrophotometric determination of surfactants in water

The novel and simple methods for the sensitive determination of cationic and anionic surfactants in water based on effervescence assisted dispersive liquid–liquid microextraction and microvolume UV-Vis spectrophotometry have been developed. The method involves ion-pair extraction of cationic and anionic surfactants with organic dyes (methyl orange and azure A, respectively) during the dispersion of extraction solvent (CHCl₃) by CO₂ bubbles which are formed by the injection of a mixture of the extraction solvent and proton donor solvent into the sample solution which contains carbonate-ions as effervescency agent. The analytical performance of the proposed procedure was compared with the conventional dispersive liquid–liquid microextraction. Appropriate experimental conditions for both methods were investigated. The absorbances of the colored extracts at wavelengths of 440 and 625 nm obey Beer's law within the range of 0.1–5.0 mg/L for both cationic and anionic surfactants. The limit of detection (LOD) obtained using the effervescence assisted extraction method was 30 µg/L for cationic and anionic surfactants. The proposed methods were successfully applied to determination of surfactants in water samples.     

Wool-waste as organic nutrient source for container-grown plants

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6–5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2–5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO₃–N and NH₄–N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers’ surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.     

Assessing the physiological state of woody plants by parameters of chlorophyll fluorescence in the bark of annual shoots

The relative yield of variable chlorophyll fluorescence in the bark of annual shoots of woody plants was measured with a portable pulse-modulated fluorometer designed for this purpose at the Department of Biophysics (Biological Faculty, Moscow State University). Experiments were performed to study the response of this parameter to external influences (treatment with an herbicide, water loss, etc.). The results demonstrated the possibility of reliably recording the parameters of fluorescence in the annual shoots of various woody plants without damaging these shoots. It is concluded that measurements of chlorophyll fluorescence in the bark of woody plants can be used for analyzing changes in the physiological state of tree stands under the effects of natural and anthropogenic factors.     

Physiopathology and effectiveness of therapeutic vaccines against human papillomavirus

Environmental Science and Pollution Research - Human papillomavirus (HPV) is a well-known sexually transmitted disorder globally. Human papillomavirus (HPV) is the 3rd most common cancer that...     

ICZM in the Black Sea region: experience and perspectives

Sustainable development of the Black Sea countries is aimed at increase of living standards of population together with maintenance of the unique ecosystems in the region. This process is impossible without development of an efficient system of Integrated Coastal Zone Management (ICZM) in every state and at the regional level. Presence of similar social, economic, and ecological problems, most of them of transboundary character, calls for the necessity of close cooperation of all Black Sea states in creating and improving their national ICZM systems, and in finding also regional solutions. The ICZM activities in the Black Sea region date back to the signing of the Convention on the Protection of the Black Sea Against Pollution (Bucharest Convention) in 1992. The first steps and achievements in ICZM within the Black Sea region for 15 years are presented in this paper and further steps are outlined.     

Optimization of pulp mill effluent treatment with catalytic adsorbent using orthogonal second-order (Box-Behnken) experimental design

Novel catalytic adsorbent (ruthenium on carbon) was employed for the treatment of pulp mill effluent in the presence of hydrogen peroxide. Mathematical model and optimization of the process regarding the most favorable COD (%), TOC (%) and color (%) removal rates was developed and performed with experimental design taking into account catalytic adsorption process kinetics. As the initial experimental design, 3(3-1) half-fractional factorial design (H-FFD) was accomplished at two levels to study the significance of the main effects, such as catalytic adsorbent (g l(-1)) and hydrogen peroxide (ppm) concentrations using the response surface methodology (RSM). Finally, a four factor-three coded level central composite design (CCD) with 28 runs was performed in order to fit a second-order polynomial model. Validation of the model was accomplished by different criteria including coefficient of determination and the corresponding analysis of variance. The achieved removal rates for TOC (up to 75%), COD (up to 73%) and color (up to 68%) were observed for the defined optimal conditions: 1g l(-1) of ruthenium on carbon, 7 ppm of hydrogen peroxide, pH = 4 and ambient temperature. The proposed method benefited significantly improved TOC, COD and color removal efficiency, regenerability and reusability of the catalytic adsorbent and unaltered initial pH of an effluent in comparison to traditional adsorption or oxidation processes.     

Oxygen isotope fractionation between bird bone phosphate and drinking water

Oxygen isotope compositions of bone phosphate (δ¹⁸O_p) were measured in broiler chickens reared in 21 farms worldwide characterized by contrasted latitudes and local climates. These sedentary birds were raised during an approximately 3 to 4-month period, and local precipitation was the ultimate source of their drinking water. This sampling strategy allowed the relationship to be determined between the bone phosphate δ¹⁸O_p values (from 9.8 to 22.5‰ V-SMOW) and the local rainfall δ¹⁸O_w values estimated from nearby IAEA/WMO stations (from ?16.0 to ?1.0‰ V-SMOW). Linear least square fitting of data provided the following isotopic fractionation equation: δ¹⁸O_w = 1.119 (±0.040) δ¹⁸O_p ? 24.222 (±0.644); R ² = 0.98. The δ¹⁸O_p–δ¹⁸O_w couples of five extant mallard ducks, a common buzzard, a European herring gull, a common ostrich, and a greater rhea fall within the predicted range of the equation, indicating that the relationship established for extant chickens can also be applied to birds of various ecologies and body masses. Applied to published oxygen isotope compositions of Miocene and Pliocene penguins from Peru, this new equation computes estimates of local seawater similar to those previously calculated. Applied to the basal bird Confuciusornis from the Early Cretaceous of Northeastern China, our equation gives a slightly higher δ¹⁸O_w value compared to the previously estimated one, possibly as a result of lower body temperature. These data indicate that caution should be exercised when the relationship estimated for modern birds is applied to their basal counterparts that likely had a metabolism intermediate between that of their theropod dinosaur ancestors and that of advanced ornithurines.