Synthesis, antibacterial, and antioxidant studies of 7-amino-3-(4-fluorobenzoyl)indolizine-1-carboxylate derivatives

In the present work, the quaternary salts of 4-aminopyridine, i.e., 4-amino-1-[2-(4-bromophenyl)-2-oxoethyl]pyridin-1-iumbromides were obtained by stirring 4-aminopyridine with phenacyl bromides in acetone at room temperature separately.These quaternary salts of 4-aminopyridine were treated with acetylenes (electron deficient), in the presence of anhydrouspossium carbonate in N,N-dimethylformamide solvent to get indolizine derivatives. The structures of newly synthesisedcompounds have been confirmed by spectroscopic techniques, such as liquid chromatography mass spectrometry,1H-NMR, and elemental analysis. Synthesized all compounds were screened for antibacterial and antioxidant activity.The compounds 2e, 2g, and 2j shows inhibition zone against bacteria and compounds 2a and 2f moderately active againstbacteria. All compounds 2a to 2j show 1,1-diphenyl-2-picrylhydrazide radical free radical scavenging activity, NitricOxide free radical scavenging activity, Reducing power scavenging activity, and Lipid peroxidation inhibition activity.

Effect of UV-C on thylakoid arrangement, pigment content and nitrogenase activity in the cyanobacterium Microchaete sp.

The effect of UV-C radiation on thylakoid arrangement, chlorophyll-a and carotenoid content and nitrogenase activity of the cyanobacterium Microchaete sp. was studied. Chlorophyll-a and carotenoid content increased gradually up to 48 h of UV-C exposure but declined with longer exposures. Nitrogenase activity decreased moderately with 6 to 12 h exposure and decreased substantially afterwards. When cells exposed to UV-C for 12 to 24 h, grown under fluorescent light for 144 h, nitrogenase activity increased to levels greater than in the control cells. The exposure of UV-C treated cells to fluorescent light, however, did not result in recovery of pigment content. In Microchaete sp. cells treated with UV-C for 144 h, thylakoid membranes became dense, were aggregated into bundles, and were surrounded by spaces devoid of cytoplasm.

Amadurecimento de manga 'Ubá' com etileno e carbureto de cálcio na pós-colheita / Ripening of 'Ubá' mango using ethylene and calcium carbide

Mangas 'Ubá' fisiologicamente maduras foram tratadas com etileno ou carbureto de cálcio (CaC2) visando à antecipação e à uniformização do amadurecimento. Frutos com massa média de 133,8±1,9g foram expostos às doses de 0, 20, 40, 80 e 160g de CaC2 m-3 de câmara ou 0, 50, 100, 200 e 400mL de etileno m-3 de câmara durante 24h, em câmaras a 18,1±0,7°C e 90±3 por cento de UR. Após o tratamento, os frutos permaneceram sob as mesmas condições de temperatura e UR, e foram avaliados aos 0, 1, 3, 6, 9, 12 e 15 dias de armazenamento. O etileno e o CaC2 acentuaram a perda de massa das mangas. Nos frutos tratados com CaC2, o pico climatérico respiratório ocorreu aos 3, 6, 9, 9 e 12 dias de armazenamento para as doses 160, 80, 40, 20 e 0g/m³, respectivamente. Nos frutos tratados com etileno, este pico foi registrado aos 3, 3, 6, 6 e 12 dias de armazenamento para as doses 400, 200, 100, 50 e 0mL m-3, respectivamente. Todas as doses de CaC2 e de etileno aceleraram a perda de firmeza, o aumento do teor de sólidos solúveis e de carotenóides, a redução da acidez e a mudança de cor da casca e da polpa dos frutos. Por outro lado, esses produtos também acentuaram a perda de eletrólitos celulares e de ácido ascórbico. Nos frutos tratados com etileno, a queda da firmeza foi mais brusca em relação aos tratados com CaC2. No entanto, o extravasamento de solutos foi maior para frutos tratados com CaC2. O aumento no teor de sólidos solúveis foi proporcional ao aumento das doses de CaC2 e de etileno. Doses de 20g de CaC2 e 50mL de etileno por m³ de câmara foram suficientes para antecipar e uniformizar o amadurecimento de manga 'Ubá'.

Physiologically mature 'Ubá' mangoes were treated with ethylene or calcium carbide (CaC2) aiming to accelerate and standardize fruit ripening. Fruits with mean weight of 133.8±1.9g were treated with concentrations of 0, 20, 40, 80 and 160g CaC2 chamber m-3 and 0, 50, 100, 200 and 400mL of ethylene/chamber m³, in chambers at 18.1±0.7°C and 90±3 percent RH, for 24h. After the treatment, the fruits were kept under the same conditions of temperature and RH, and were evaluated at 0, 1, 3, 6, 9, 12 and 15 days of storage. Ethylene and CaC2 increased mass loss of the fruits. Mangoes treated with CaC2 showed the respiratory climacteric peak at 3, 6, 9, 9 and 12 days of storage for the concentrations 160, 80, 40, 20 and 0g m-3, respectively. Fruits treated with ethylene showed the peak at 3, 3, 6, 6 and 12 days of storage for the concentrations 400, 200, 100, 50 and 0mL m-3, respectively. All concentrations of CaC2 and ethylene accelerated the loss of firmness, the increase of soluble solids and carotenoids, the reduction of acidity and the change in color of skin and pulp. However, these products also increased electrolyte leakage and decreased ascorbic acid content. Fruits treated with ethylene showed sharper firmness loss compared with fruits treated with CaC2. On the other hand, solute leakage was higher in fruits treated with CaC2. Soluble solids content increased with increasing concentrations of CaC2 and ethylene. The concentrations of 20g of CaC2 and 50mL of ethylene per chamber m³ were sufficient to accelerate and uniformize ripening of 'Ubá' mango.

Peanut agglutinin induced alterations in capsular and extracellular polysaccharide synthesis and ex -planta nitrogenase activity of cowpea rhizobia.

The root exudate of Arachis hypogea (groundnut) and its seed lectin peanut agglutinin were found to stimulate the synthesis of exopolysaccharide and capsular polysaccharide of the microsymbiont cowpea Rhizobium strain JLn (c). The synthesis of capsular polysaccharide was enhanced 1·5-fold and 2-fold in the presence of peanut agglutinin and root exudate, respectively. The synthesis of capsular polysaccharide was suppressed in the presence of different forms of combined nitrogen. Quantitative differences were also detected between the exopolysaccharide of cells grown in the presence and absence of root exudate. Electron microscopic examination of negatively stained lectin-treated JLn (c) cells showed an increased deposition of capsular polysaccharide surrounding the cells. Hurthermore, ex planta nitrogenase activity of JLn(c) cells in the presence of lectin was found to be enhanced by 63% in correlation with the increased synthesis of polysaccharides.