Fungicidal activity and molecular modeling of fusarubin analogues from Fusarium oxysporum

Abstract

Fusarubin analogues of Fusarium oxysporum f. sp. ciceris were investigated for antifungal activity in vitro against five soil borne phytopathogenic fungi. 3-O-Methyl-8-O-methyl-fusarubin was inhibitory towards S. sclerotiorum (EC₅₀ 0.33?mmol L^?1) and Sclerotium rolfsii (EC₅₀ 0.38?mmol L^?1). A structure–antifungal activity relationship of fusarubin analogues was established from their activity performance. Possible mechanism of action of these compounds was studied using molecular docking and simulations against three target enzymes which revealed receptor ligand binding affinity. Docking of 3-O-methyl-8-O-methyl-fusarubin into the succinate dehydrogenase site revealed formation of salt bridge, hydrogen bond, π–anion, π–alkyl, and Van der Waals interactions.     

The role of root organic acids in the tolerance of Festuca rubra to zinc,lead and cadmium

Abstract

Festuca rubra L. plants are pseudometallophytes colonizing abandoned Pb/Zn mine areas, successfully employed in phytostabilization. To study the contribution of low-molecular weight organic acids to metal tolerance, F. rubra plants were grown for three months in hydroponics with Cd (1.8, 18 and 36 µmol?L^?1), Pb (50, 250 and 500?µmol?L^?1) and Zn (0.3, 3 and 6?mmol?L^?1), separately, and in ternary combination (18?µmol?L^?1 Cd + 250?µmol?L^?1 Pb + 0.3?mmol?L^?1 Zn). The roots retained most of the metals but their distribution from shoot to root was altered when the plants were treated with the ternary combination. The main organic acids in roots were citrate and malate. At the lowest concentrations, the metals caused small reductions in biomass, had no effects on photosynthetic pigments nor on malondialdehyde, but led to increases in root organic acids. At higher concentrations, phytotoxic responses were observed, associated with a decline of citrate and malate in the roots.     

Factors driving the seasonal dynamics of Pseudo-nitzschia species and domoic acid at mussel farming in the SW Mediterranean Sea

ABSTRACT

The seasonal variations in Pseudo-nitzschia species and domoic acid (DA) concentration were investigated, at three shellfish farms in SW coastal Mediterranean. In parallel, the toxicity of mussels was tested. Two distinct groups of species were enumerated according to morphology and size (Pseudo-nizschia delicatissima and P. seriata groups). DA was detected over a nine-week period from July to October 2012 in the Lagoon, with a maximum concentration recorded in July (12.71?ng?DA?L^?1). DA was positively correlated with the presence of P. seriata-group and P. delicatissima-group and was mostly occurred during P limitation period in seawater. No DA was found in mussels that were collected during the period of DA absence in seawater. Our results suggest that temperature, salinity, inorganic and organic nutrients were significant for the seasonal dynamics of P. seriata and P. delicatissima groups, but that the P limitation was the most driving factor for DA production in these areas. The relative influence of environmental factors should be further studied to better understand the recent surfacing of massive blooms of toxigenic Pseudo-nitzschia in SW Mediterranean coast.     

Larvicidal,repellent, and histopathologic effects of Citrullus colocynthis against the malaria vector

Abstract

This research is conducted to determine the larvicidal, repellent and pathological effects of fruit extracts of C. colocynthis on malaria vector mosquito, Anopheles stephensi Liston, 1901. The fruit water and ethanol extract of C. colocynthis were concentrated for larvicidal and repellent activities on human volunteer against An. stephensi. The temephos larvicide was tested as the positive control. A concentration of 300?mg/L had full-scale mortality and the most toxic effect. The LC₅₀ and LC₉₀ values of C. colocynthis water and ethanol extracts were 180and 283?mg/L, respectively. The LC₅₀ and LC₉₀ values of temephos were 0.2706 and 1.6932?mg/L, respectively. The ED₅₀ and ED₉₀ values of the plant extract were 0.2 and 1.3?mg/cm², respectively. Thin sections from treated larvae exhibited gross histopathologic effects of C. colocynthis fruit extracts on gut epithelial cell layer by vacuolization of foregut cuboidal and midgut columnar cells. This study suggested that the fruit extracts of C. colocynthis had significant larvicidal and repellent activity to be used as an ideal approach to control the malaria vector mosquito.     

17α-Ethinylestradiol in Lakes of Hanoi and its effect on seed germination

Abstract

The lakes of Hanoi are important water resources for urban agriculture. The concentrations of 17α-ethinylestradiol in the water of three major lakes were found to range from 0.1 to 9.1?ng/L, peaking during the rainy season. Effects at levels from 1?ng/L to 1?µg/L on the germination of mung bean (Vigna radiata) and bok choy (Brassica rapa) were studied. Soaking the seeds in solutions containing 17α-ethinylestradiol at 10?ng/L and higher increased the germination rate of mung bean but not of bok choy. For the latter, irrigation after sowing with solutions containing 17α-ethinylestradiol at 10?ng/L and higher accelerated germination.

Abbreviations: MNRE: Ministry of Natural Resources and Environment; PE₆₀: Population equivalent; USGS: U.S. Geological Survey; SPE: Solid phase extraction; EDTA: Disodium ethylenediaminetetraacetate; HPLC: High performance liquid chromatography; ELISA: Enzyme-linked immunosorbent assay; DOM: Dissolved organic matter; EEQ: Estradiol equivalent     

Regression models for octanol‐water partition coefficients,and for bioconcentration in fish

Octanol‐water partition coefficients (P) of a number of organochlorine insecticides (OCs) are presented. The merits of log‐log regressions between experimental ? values and calculated estimates of P, solute activity coefficients in water, solute molecular surface area data, and reversed‐phase liquid‐chromatographic net retention data, are critically evaluated for several classes of pollutants: polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes, chlorinated biphenyls and OCs. Special attention is paid to the predictive accuracy of such semi‐empirical regressions in connection with possible effects of solute molecular shape and polarity.

Finally, bioconcentration and ‐accumulation of hydrophobic pollutants in fish are briefly discussed.     

Selenium improves physiological responses and nutrient absorption in wheat (Triticum aestivum L.) grown under salinity

Abstract

Salinity is a serious limiting factor for crop growth and production. The present study was conducted to investigate the response of wheat grown at salinities of 0.12, 0.30 and 0.60?S?m^?1 on soil supplemented with 0, 0.5, 1 and 4?mg?kg^?1 Se as selenite. Chlorophyll a and b, carotenoid contents, Fe, Zn and Se in shoots as well as shoot dry weight were negatively affected by increased salinity. Se had a dual effect: at 0.5?mg?kg^?1, chlorophyll b, proline, and shoot Fe content were increased, catalase activity was stimulated; there was no effect on Zn content and shoot dry weight. At the two higher concentrations, Se led to decreases in chlorophyll content, nutrient concentration, and shoot dry weight. Thus, moderate addition of Se to soil could be a strategy to improve physiological responses and micronutrient status in wheat under salinity stress.     

Sustainable development and cultural theory

SUMMARY

What is sustainable development? Why is at an issue? Ideally, what needs to be done? and Practically, what can be done? are answered here by relying on the cultural theory of Mary Douglas and her colleagues, more especially Aaron Wildavsky and Michael Thompson, both of whom have used the model to address sustainable development. The implications of cultural theory for sustainable development are substantial.

The article is divided into five sections. The first describes the current controversy over sustainable development. The second sets out the cultural theory model, and the third applies that model to reformulate our understanding of sustainable development. The fourth draws out the implications of a reformulated sustainable development, while the conclusion uses those implications to answer the four questions that started the article.     

Primary production of phytoplankton at a frontal zone located at the northern slope of the Dogger Bank (North Sea)

In July 1988 a survey was made in the Dogger Bank area of the North Sea. As a result of wind stress the area was found to be frequently well mixed. At the northerly slope a transition zone was observed between the stratified central North Sea and the well-mixed Dogger Bank area. Low nutrient concentrations were observed in surface waters; especially for nitrate (<0,1µM). High concentrations of phosphate (>0,5µM), nitrate (>1µM), ammonium (>2µM) and silicate (>2µM) only prevailed below the thermocline. Chlorophylla values were below 1µg l^–1 near the surface. Enhanced values (up to 4µg l^–1) were observed in the deeper layer at the transition zone and just below the thermocline at well-stratified locations. At the transition zone high specific C-fixation rates (up to 100 mg C mg^–1 chla d^–1) at the surface indicated the presence of enhanced productivity. The compensation depth for primary production was found to coincide with a specific C-fixation rate of 5 mg C mg^–1 chla d^–1. At greater depths, phytoplankton was only found where tidally induced vertical mixing allowed a regular exposure to higher light intensities. Storms resulted in a rapid redistribution of chlorophylla and enhancement of the C-fixation rate in the upper layer of the water column.Publication No. 10 of the project Applied Scientific Research Netherlands Institute for Sea Research (BEWON)     

Integral approach to industrial effluent quality control in favour of preventing the Rijeka bay pollution

Abstract

INA‐Petrochemical Industry Omi?alj, Yugoslavia is currently producing low density polyethylene, vinyl chloride monomer and ethylene dichloride.

Because of a potentially great hazard for environmental pollution, particularly by low molecular weight chlorinated hydrocarbons, the company has been putting significant effort into its anti‐pollution programme.

Modern technology, polyfunctional organization and proper control of all waste materials has enabled, thus far, no evident or noticable impact on the environment.

Wastewater treatment from the source to final discharged effluent and environmental control results are described.     

Effect of Pb,Cd and Cu on survival and development of Culex quinquefasciatus (Diptera: Culicidae)

ABSTRACT

The present research aimed to determine the lowest levels of three heavy metals (Pb, Cd and Cu) to which the larvae of Southern House Mosquito, Culex quinquefasciatus are susceptible in water. The study also aimed to investigate the effects of these heavy metals on the development of Cx. quinquefasciatus at concentrations set by Pakistan Environmental Protection Agency (Pak-EPA) as permissible levels for liquid industrial effluents. The 2nd instar larvae of Cx. quinquefasciatus were exposed to different concentrations of Pb, Cd and Cu and their effects on oviposition preference, egg hatching rate and larval development were studied. The LC₅₀ values of Pb, Cd and Cu were 12.6, 6.3 and 2.6?ppm, respectively. Gravid female mosquito adults deposited a significantly lower number of egg rafts in containers containing 0.50?ppm Pb or 1.0?ppm Cu in water. Each of the heavy metals in water resulted in significantly (p?<?0.05) lower egg hatching rate, prolonged time to pupation, lower pupation rate, prolonged time to adult emergence, lower adult emergence rate and higher female to male ratio. It is concluded that the 2nd instar larvae of Cx. quinquefasciatus are susceptible to Pak-EPA permissible levels of Pb, Cd and Cu in municipal and liquid industrial effluents.     

Acute nitrate poisoning in two cattle

Abstract

The rate and product composition during photooxidation of aromatic hydrocarbons (toluene, o‐, m‐, p‐xylene and cumene) dissolved in n‐hexane and spread as a liquid film on water is reported. The photo degradability of these chemicals is 10–20%. The products identified are oxygenated aromatic compounds. It is observed that the absorption bands of the compounds under investigation depend upon the partial pressure of dissolved oxygen and these bands extend up to 290 nm. The new absorption band around 290 nm is probably due to broadening of ¹L_b bands which is responsible for direct photolysis.

stream. We have been especially interested in investigating the rate of disappearance and distribution of main oxidation products in two phases. Besides that an attempt has been made to throw some light on the reaction mechanism.     

Role of the necrosis factor-κB pathway in dibutyl phthalate mediated effects on human glioma cells

Abstract

The human glioma cell line U251 was incubated for 12?h and 24?h in medium containing dibutyl phthalate at concentrations of 25?µmol/L and 100?µmol/L. Decreased cell viability and increased oxidative stress show the cytotoxicity of dibutyl phthalate. Nuclear factor-κB and nuclear factor-κB pathway-related proteins were altered, which could be attenuated by vitamin E at 20?µmol/L. Thus, dibutyl phthalate induces cytotoxicity through activation of nuclear factor-κB and vitamin E exerts neuroprotection against dibutyl phthalate-mediated cytotoxicity in vitro.     

Growth and herbivory by heterotrophic dinoflagellates in the Southern Ocean,studied by microcosm experiments

Growth and herbivory of heterotrophic dinoflagellates (Gymnodinium sp.) from the Weddell Sea and the Weddell/Scotia Confluence were studied in 1988 in 100-liter microcosms. The microcosms were screened through 200-µm or 20-µm mesh nets and incubated for 12 d at 1 °C under artificial light. Mean cell volume of dinoflagellates was 1 000 to 1 500µm³, and that of their phytoplankton prey 360 to 430µm³. Dinoflagellate growth rate followed a Holling type II functional response, with a maximum growth rate of 0.3 d^–1 and half-saturation food concentrations of 1.0µg chlorophylla l^–1, 50µg C l^–1, or 1 500 cells ml^–1. Carbon budgets based on¹⁴CO₂ assimilation and biomasses of phytoplankton and heterotrophic dinoflagellates suggested a balance between phytoplankton grazing loss and dinoflagellate consumption, assuming a dinoflagellate carbon conversion efficiency of 40%. Applying this to the functional response yielded estimates of maximum ingestion rate (0.8µg Cµg^–1 C d^–1, or 6 pg C dinoflagellate^–1 h^–1) and maximum clearance (0.8 to 1.2 × 10⁵ body volumes h^–1, or 80 to 120 nl ind.^–1 h^–1). The microcosm experiments suggested that heterotrophic dinoflagellates may contribute significantly to maintenance of low phytoplankton biomass in the Southern Ocean.     

Response of the microbial food web to manipulation of nutrients and grazers in the oligotrophic Gulf of Aqaba and northern Red Sea

The control mechanisms within the pelagic microbial food web of the oligotrophic Gulf of Aqaba and the northern Red Sea were investigated in the spring of 1999. Nutrient conditions and potential grazer impact were manipulated in a series of dilution experiments. Ambient nutrient concentrations and autotrophic biomass were very low (0.23–1.21 µmol NO₃ l^–1, 0.06–0.98 µmol NH₄ l^–1, 1.08–1.17 µmol Si l^–1, 0.08–0.12 µmol P l^–1, 0.15–0.36 µg chlorophyll a l^–1). The planktonic community was characterized by low abundances [3.0–5.5×10⁵ heterotrophic bacteria ml^–1, 0.58–7.2×10³ ultraphytoplankton <8 µm ml^–1 (small eukaryotic photoautotrophs and Prochlorococcus sp., excluding Synechococcus sp.), 0.45–4.4×10⁴ Synechococcus sp. ml^–1, 0.32–1.2×10³ heterotrophic nanoflagellates ml^–1, 1.3–3.8×10³ phytoplankton >8 µm l^–1, 0.93–5.4×10² microzooplankton l^–1] and dominated by small forms (0.2–8 µm). Dinoflagellates and oligotrichous ciliates were the most common groups in initial samples among the phytoplankton >8 µm and microzooplankton, respectively. Results show that bottom-up and top-down control mechanisms operated simultaneously. Small organisms were vulnerable to grazing, with maximum grazing rates of 1.1 day^–1 on heterotrophic bacteria and 1.3 day^–1 on ultraphytoplankton. In contrast, algae >8 µm showed stronger signs of nutrient limitation, especially when the final assemblages were dominated by diatoms. Synechococcus sp. were not grazed and only showed moderate to no response to nutrient additions. The high spatial and temporal variation of our results indicates that the composition of the planktonic community determines the prevailing control mechanisms. It further implies that, at this transitional time of the year (onset of summer stratification), the populations fluctuate about an equilibrium between growth and grazing.Communicated by O. Kinne, Oldendorf/Luhe     

Temporal dynamics of arsenic uptake and distribution: food and water risks in the Bengal basin

Abstract

Contaminated food chain is a serious contender for arsenic (As) uptake around the globe. In Nadia, West Bengal, we trace possible means of transfer of As from multiple sources reaching different trophic levels, and associated seasonal variability leading to chronic As uptake. This work considers possible sources-pathways of As transfer through food chain in rural community. Arsenic concentration in groundwater, soil, rice, and vegetable-samples collected detected in different harvest seasons of 2014 and 2016. Arsenic level in shallow groundwater samples ranged from 0.1 to 354?µg/L, with 75% of the sites above the prescribed limit by WHO (10?µg/L) during the boro harvest season. High soil As content (～20.6?mg/kg), resulted in accumulation of As in food crops. A positive correlation in As conc. with increase over period in all sites indicating gradual As accumulation in topsoil. Unpolished rice samples showed high As content (～1.75?mg/kg), polishing reduced 80% of As. Among vegetables, the plant family Poaceae with high irrigation requirements and Solanaceae retaining high moisture, have the highest levels of As. Contaminated animal fodder (Poaceae) and turf water for cattle are shown to contaminate milk (0.06 to 0.24?µg/L) and behoves strategies, practices to minimize As exposure.     

Soil biological characteristic,nutrient contents and stoichiometry as affected by different types of remediation in a smelter-impacted soil

ABSTRACT

In order to evaluate the ecological risk reductions of copper (Cu) and cadmium (Cd) and the change of nutrient contents and stoichiometry in a smelter-impacted farmland in Guixi, Jiangxi Province, China, with ～ 800?mg Cu kg^?1 soil and 0.8?mg Cd kg^?1 soil, an three years in situ experiment was conducted. The field trial consisted of 4 ×?5?m plots in a completely randomised block design. Hydroxyapatite was added at 10?g kg^?1 soil and Sedum plumbizincicola, Elsholtzia splendens, and Pennisetum sp. were planted. Post-treatment soil and plant samples were collected annually and analysed for Cu and Cd bioaccessibility, soil carbon: nitrogen: phosphorus (C:N:P), and the stoichiometries of soil β-glucosidase (BG), N-acetylglucosaminidase (NAG), and acid phosphatase (AP) activity levels. The results indicated that the hydroxyapatite treatments significantly reduced Cu and Cd bioaccessibility as well as the ratio of C:P and N:P. Moreover, BG, NAG, and AP activity levels all increased relative to those in untreated soil. Plants may also influence soil BG, NAG, and AP activity. This study demonstrated that in situ Cu and Cd stabilisation by hydroxyapatite and phytoextraction is ecologically safe and can alter soil mineral nutrient ecological stoichiometry and enzyme activity.     

Interactive accumulation of mercury and selenium in the sea starAsterias rubens

Interactions between mercury and selenium accumulation and subcellular binding inAsterias rubens (L.), collected in 1987 from Lille Bælt at Middelfart, Funen, Denmark, were investigated in laboratory experiments. Sea stars exposed to 10µg Hg l^–1 for 30 d accumulated mercury in body wall, tube feet and stomach linearly with time at 1.2, 1.2 and 0.5µg Hg g^–1 dry wt d^–1, respectively. Mercury was accumulated in pyloric caeca and coelomic fluid initially at 1.4µg Hg g^–1 dry wt d^–1 and 9.4 ng Hg ml^–1 d^–1, respectively; after 10 d uptake rates decreased. Sea stars exposed to 75µg Se-SeO ₃ ^{- -} l^–1 accumulated selenium linearly with time over 30 d in the stomach, pyloric caeca, tube feet and body wall at 2.0, 1.2, 1.2 and 0.6µg Se g^–1 dry wt d^–1. Sea stars exposed to 75µg Se-SeO ₄ ^{- -} l^–1 maintained selenium levels in the coelomic fluid at 75µg Se l^–1 over 30 d. Exposure to selenate did not alter the selenium concentrations in the tissues. Sea stars exposed concurrently to 75µg Se-SeO ₃ ^{- -} and 10µg Hg l^–1 accumulated more mercury and selenium in tube feet and body wall than did sea stars exposed to the two elements alone. In pyloric caeca and stomach concurrent exposure reduced accumulation of both elements. Mercury was bound predominantly in the insoluble fraction of the tissues, and soluble mercury was bound in proteins of high (> 70 kilodaltons) or very low (< 6000 daltons) molecular weight. Ca. half of the selenium recovered was bound in the insoluble fraction, and soluble selenium was bound in proteins of high (> 70 kilodaltons) or very low (< 6000 daltons) molecular weight. Interaction between the two elements was exerted predominantly in the insoluble fraction of the tissues.     

Analytical studies on the pollution of argeş river

Using two analytical techniques (ICP‐AES and ASV) the heavy metal pollution of Arge? River was studied. These techniques are characterized by similar analytical performances.

The samples were collected from 13 sites starting from Capra Lake (altitude 2241 m) and finishing at Oltenita city (altitude 10 m).

Arge? River is the fifth longest river in Romania after Siret, Mure?, Olt and Some?, its length is 340 km and the river flows through four cities, Curtea de Arge?, Pite?ti, Gae?ti and Oltenita.

The results of the determinations of Cu, Cd, Zn and Pb, indicate that the Arge? River shows relatively low pollution.