Synthesis and structure of a terminal uranium nitride complex

The terminal uranium nitride linkage is a fundamental target in the study of f-orbital participation in metal-ligand multiple bonding but has previously eluded characterization in an isolable molecule. Here, we report the preparation of the terminal uranium(V) nitride complex [UN(Tren(TIPS))][Na(12-crown-4)(2)] {in which Tren(TIPS) = [N(CH(2)CH(2)NSiPr(i)(3))(3)](3-) and Pr(i) = CH(CH(3))(2)} by reaction of the uranium(III) complex [U(Tren(TIPS))] with sodium azide followed by abstraction and encapsulation of the sodium cation by the polydentate crown ether 12-crown-4. Single-crystal x-ray diffraction reveals a uranium-terminal nitride bond length of 1.825(15) angstroms (where 15 is the standard uncertainty). The structural assignment is supported by means of (15)N-isotopic labeling, electronic absorption spectroscopy, magnetometry, electronic structure calculations, elemental analyses, and liberation of ammonia after treatment with water.     

No DNA loss in autotetraploids of Arabidopsis thaliana

To address the issue of genome evolution in autopolyploids and particularly to investigate whether rapid sequence elimination also occurs in autopolyploids as in allopolyploids, amplified fragment length polymorphism (AFLP) fingerprinting was employed to examine a large number of genomic loci in F₁ hybrids between two different autotetraploids of Arabidopsis thaliana accessions, namely Ler and Col. Using this approach, perfect additivity in the F₁ hybrids was found between the newly‐formed autopolyploids when compared with their parental lines. Using flow cytometry, the study was extended in a quantitative manner, in which the nuclear DNA contents in one autotetraploid A. thaliana accession Ler, was determined. The increase in genome size of the autotetraploid line was additive. Taken together, no evidence was found for genome size reduction due to autopolyploidization of A. thaliana. The results indicating that there was no DNA loss in autotetraploid A. thaliana suggest that a different type of genome evolution may occur in autopolyploids during the initial stages of their formation when compared with allopolyploids.     

A Clinico-pathological study on the effect of vincristine on transmissible venereal tumour in dogs

Transmissible venereal tumour (TVT) is a coitally transmitted neoplasm of dogs and is common among sexually active dogs, where sexual behaviour is not under control. Several treatment options are available for the treatment of the tumour, with chemotherapy being the most commonly employed. In this study, we investigated the clinical and cytological changes after weekly vincristine sulphate administration in 38 cases of naturally occurring TVT. Tumours totally regressed in 31 dogs after two to seven doses (mean 3.54 +/- 1.01) of vincristine. One dog died after the fifth dose of vincristine, and in six dogs, an additional treatment with doxorubicin was needed. Masses were still present in four dogs and the histopathological examination revealed small nodules of granulation tissue in two dogs, while viable tumour cells were identified in the remaining two cases. No recurrences were observed in a follow-up period of 7-49 months (mean 13.64 +/- 9.66); in one dog, granulation tissue was detected in the surgery site after 2 months. Treatment success could easily be followed by the cytological changes. In conclusion, vincristine was found to be effective chemotherapeutic agent.     

POTASSIUM SULFATE IMPROVES WATER DEFICIT TOLERANCE IN MELON PLANTS GROWN UNDER GLASSHOUSE CONDITIONS

Interactive effects of water stress and potassium (K) on some physiological attributes and nutritional status of melon (Cucumis melo L. cv. ‘Tempo F1’) plants were assessed in a pot experiment. Treatments used were: (1) control or well-watered (WW) + K1, (2) WW + K2, (3) WW + K3, (4) water stress (WS) + K1, (5) WS + K2, and (6) WS + K3. Water stress (WS) was imposed by maintaining the moisture level equivalent to 50% pot capacity, whereas well-watered (WW) pots (control) were maintained at full pot capacity (100% PC). Hoagland's nutrient solution was modified to supply K as potassium sulfate (K₂SO₄) at 6, 9, and 12 mM for K1, K2, and K3 treatments, respectively. Water stress reduced fruit yield, total dry matter, chlorophyll content and relative water content (RWC), but increased proline accumulation in the melon plants. However, additional supply of K as 3 or 6 mM significantly enhanced all the earlier mentioned physiological parameters, but the values were still not the same as the levels of the control treatment. Water stress also reduced leaf calcium (Ca) and K of the melon plants, but additional supply of K to the root zone increased the levels of both nutrients much higher than those at the control (C) treatment. Our study revealed that additional supply of K improved water stress tolerance in melon plants by enhancing chlorophyll, relative water content and concentrations of some essential nutrients in leaves.     

Optimization of Process Parameters for Removal of Arsenic Using Activated Carbon-Based Iron-Containing Adsorbents by Response Surface Methodology

Rhizoremediation is a complex type of green clean-up technology that involves both plants and the rhizosphere-associated microorganisms to decompose hazardous compounds. The success of the strategy strongly depends on plant tolerance towards the pollutant, as well as plant's interactions with the rhizospheric microbes. The microorganisms may be stimulated by the secreted root exudates, which results in an increased breakdown of contaminants in the rhizosphere. The main goal of this study was to establish a potential rhizoremediation combination for a diesel-polluted site. Inoculation of plant roots or seeds with indigenous rhizospheric populations is a common approach in the rhizoremediation. However, we introduced hydrocarbon-degrading consortia (M10, R3, and K52) that were previously isolated from crude oil-contaminated soil instead of indigenous microbes. Bioaugmentation with these petroleum degraders was applied to screen four high biomass crop species (Indian mustard, alfalfa, high erucic acid rapeseed, HEAR, and low erucic acid rapeseed, LEAR) for their tolerance towards diesel oil. At no pollution, a promoting effect of M10 bacteria could be observed on germination and root elongation of all plant species. Moreover, M10 consortiums increased the germination index at 6,000 mg diesel oil per kilogram dry soil in the case of Indian mustard, alfalfa, and HEAR. The latter species was found to increment its dry weight upon bioaugmentation with M10 bacteria and all diesel oil treatments (6,000 and 24,000 mg diesel oil per kilogram dry soil). The initial results indicate HEAR and the M10 bacterial consortium as a promising plant–microbe tandem for a long-term rhizoremediation process.

     

Effects of dietary propolis and vitamin E on growth performance and antioxidant status in juvenile rainbow trout (Oncorhynchus mykiss) under different flow rate

The present study investigated the effects of propolis and vitamin E supplementation in diets of juvenile rainbow trout subjected to two different flow rates (0.9 and 2.1 L min^?1) on growth performance, and vitamin A, C and E concentrations in tissues as well as malondialdehyde (MDA) levels. Juvenile rainbow trout were fed with diets containing 10 and 30 g propolis kg^?1, 60 mg kg^?1 vitamin E (Rovimix E‐50 adsorbate; min.%50 dl‐α‐tokopherly acetate) and without supplemented basal diet for 12 weeks. Weight gain (WG) in the C group was significantly lower (P < 0.05) than P10, P30 and E60 groups at both flow rate treatments. At 2.1 L min^?1, specific growth rate (SGR) in the C group was significantly lower (P < 0.05) than other groups, but at 0.9 L min^?1, SGR of fish did not differ among the diets groups (P > 0.05). Survival rate (SUR) was higher in propolis and vitamin E supplemented diet groups (P < 0.05) than control diet group at 0.9 L min^?1. Fish fed on diet E60 had higher (P < 0.05) tissue vitamin E concentration than fishes fed on other diets groups. Vitamin C concentration in rainbow trout tissues was significantly affected by the 30 g propolis supplemented diet group (P < 0.05), followed by the 10 g propolis supplemented diet group (P < 0.05). MDA level of E60 group was found significantly decreased instead of different than other groups (P < 0.05). The results of Student's t‐test revealed that WG, SGR, SUR values, vitamin (A, C, E) concentrations and MDA levels of tissues were negatively affected by 0.9 L min^?1flow rate treatment in juvenile rainbow trout.     

Supplementary phosphorus can alleviate boron toxicity in tomato

The effect of supplementary phosphorus on growth and yield of tomato (Lycopersicon esculentum cv. Target F1) plants grown at high boron was investigated. The results showed that high B reduced dry matter, fruit yield and chlorophyll content. High B plus 0.5 or 1 mM P increased plant dry matter, fruit yield and chlorophyll concentrations as compared to high B treatments only. Membrane permeability was not increased significantly due to high B application. In the leaves of plants grown at high boron treatments, superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) levels were increased. However, supplementary P to nutrient solution containing high B reduced the activities of the earlier mentioned enzymes in leaves but their levels were still higher than those at the control treatments. The study revealed that B status affects the activities of some antioxidant enzymes examined. Boron (B) concentrations increased in leaves and roots in the highest external B treatment as compared to the control treatment. Concentrations of Ca, P and K were significantly lower in the leaves of plants grown at high B than those in the control plants. Supplemented nutrient solution containing high B with 0.5 or 1 mM P increased the tissue concentrations of nutrients. These results indicate that supplementary P can mitigate the adverse effects of high B on fruit yield and growth in tomato plants.     

Effect of Silicon on Plant Growth and Mineral Nutrition of Maize Grown Under Water-Stress Conditions

The effect of silicon (Si) on physiological attributes and nutritional status of maize (Zea mays cv. DK 647 F1) under water stress was studied in a pot experiment. Treatments were (1) well watered (WW): 100% of FC (soil field capacity), (2) WW + Si1: 100% of FC + 1 mM Si, (3) WW + Si2: 100% of FC + 2 mM Si, (4) water stress (WS): 50% of FC, (5) WS + Si1: 50% of FC + 1 mM Si and (6) WS + Si2: 50% of FC + 2 mM Si. In the control treatment, plants were irrigated to field capacity (100% FC). Water stress was imposed by maintaining a moisture level equivalent to 50% of field capacity, whereas the well-watered pots (control) were maintained at full field capacity. Water stress was found to reduce the total dry matter (DM), chlorophyll content, and relative water content (RWC), but to increase proline accumulation and electrolyte leakage in maize plants. Both Si treatments largely improved the above physiological parameters, but levels remained significantly lower than the control (WW) values except for electrolyte leakage and root:shoot ratios, which were higher. Only root DM appeared to show very little variation in any of the treatments. The concentration of Si in the plants was increased by Si addition into the nutrient solution. Water stress reduced leaf calcium (Ca) and potassium (K) of maize plants, but addition of Si increased these nutrient levels; Ca levels were similar to WW under the high-Si treatment, but K was lower. Root Ca and K were both increased by WS; root Ca was further increased by high Si (WS + Si2 treatment). Addition of Si to the WS treatments did not change root K. Results indicate that while application of Si may be one approach to improve growth of this crop and increase its production in arid or semi-arid areas where water is at a premium, this technique would not fully substitute for an adequate water supply.     

MITIGATION EFFECTS OF SILICON ON TOMATO PLANTS BEARING FRUIT GROWN AT HIGH BORON LEVELS

Interactive effects of silicon (Si) and high boron (B) on growth and yield of tomato (Lycopercison esculentum cv. ‘191 F1’) plants were studied. Treatments were: 1) control (B1), normal nutrient solution including 0.5 mg L^?1 B (boron), 2) B1 +Si treatment: 0.5 mg L^?1 boron plus 2 mM Si, 3) B2 treatment: 3.5 mg L^?1 B, 4) B2 +Si treatment: 3.5 mg L^?1 B plus 2 mM Si, 5) B3 treatment: 6.5 mg L^?1 B, and 6) B3 +Si: 6.5 mg L^?1 B plus 2 mM Si. High B reduced dry matter, fruit yield and chlorophyll (Chl) in tomato plants compared to the control treatment, but increased the proline accumulation. Supplementary Si overcame the deleterious effects of high B on plant dry matter, fruit yield and chlorophyll concentrations. High B treatments increased the activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC. 1.11.1.7) and polyphenol oxidase (PPO; EC 1.10.3.1). However, supplementary Si in the nutrient solution containing high B reduced SOD and PPO activities in leaves, but POD activity remained unchanged. These data suggest that excess B-induced oxidative stress and alterations in the antioxidant enzymes. Boron (B) concentrations increased in leaves and roots in the elevated B treatment as compared to the control treatment. Concentrations of calcium (Ca) and potassium (K) were significantly lower in the leaves of plants grown at high B than those in the control plants. Supplementing the nutrient solution containing high B with 2 mM Si increased both nutrients in the leaves. These results indicate that supplementary Si can mitigate the adverse effects of high B on fruit yield and whole plant biomass in tomato plants.