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41.
Thereza Christina Vessoni Penna Angela Faustino Jozala Thomas Rodolfo Gentille Adalberto Pessoa Jr. Olivia Cholewa 《Applied biochemistry and biotechnology》2006,129(1-3):334-346
Nisin, a bacteriocin produced during the exponential growth phase of Lactococcus lactis ATCC 11454, inhibits the growth of a broad range of Grampositive bacteria. Gram-negative bacteria can also be inhibited by nisin with EDTA. In this study, nisin production was assayed by the agar diffusion method using Lactobacillus sake ATCC 15521 and a recombinant Escherichia coli DH5-α expressing the recombinant green fluorescent protein as the nisin-susceptible test organisms. The titers of nisin expressed and released in culture media were quantified and expressed in arbitrary units (AU/mL of medium) and converted to standard nisin concentration (Nisaplin®, 25 mg of pure nisin with an activity of 1×106 AU/mL). The expression and release of nisin by L. lactis in skimmed milk (9.09% total solids) with Man Rugosa Shepeer-Bacto Lactobacilli broth (1∶1) was monitored in a 5 L New Brunswick fermentor. Combining EDTA with nisin increased the bactericidal effect of nisin on the bacteria examined. The presence of EDTA was necessary to inhibit E. coli growth with nisin. L. sake was shown to be a good indicator for the evaluation of nisin release in the culture media, including with the addition of EDTA. 相似文献
42.
Penna Thereza Christina Vessoni Chiarini Eb Machoshvili Irene Alexeevna Ishii Marina Pessoa Adalberto 《Applied biochemistry and biotechnology》2002,98(1-9):791-802
The recombinant green fluorescent protein (gfp
uv
) was expressed by Escherichia coli DH5-α cells transformed with the plasmid pGFPuv. The gfp
uv
was selectively permeabilized from the cells in buffer solution (25 mM Tris-HCl, pH 8.0), after freezing (−70°C for 15 h), by four freeze (−20°C)/thaw cycles interlaid by sonication. The average
content of released gfp
uv
(experiment 2) was 7.76, 34.58, 39.38, 12.90, and 5.38%, for the initial freezing (−70°C) and the first, second, third and
fourth freeze/thaw cycles, respectively. Superfusion on freezing was observed between −11°C and −14°C, after which it reached
−20°C at 0.83°C/min. 相似文献
43.
Jaécio Carlos Diniz Francisco Arnaldo Viana Odaci Fernandes Oliveira Maria Aparecida M. Maciel Maria da Conceição de Menezes Torres Raimundo Braz‐Filho Edilberto R. Silveira Otília Deusdênia L. Pessoa 《Magnetic resonance in chemistry : MRC》2009,47(2):190-193
From the roots of Cordia leucocephala (Boraginaceae), two new meroterpenoid naphthoquinones, 6‐[10‐(12,12‐dimethyl‐13α‐hydroxy‐16‐methenyl‐cyclohexyl)ethyl]‐1,4‐naphthalenedione (cordiaquinone L) and 5‐methyl‐6‐[10‐(12,12‐dimethyl‐13β‐hydroxy‐16‐methenyl‐cyclohexyl)methyl‐1,4‐naphthalenedione (cordiaquinone M) were isolated. Their structures were elucidated after detailed 1D and 2D NMR (COSY, HSQC, HMBC and NOESY) data analyses and comparison with literature data for analogous compounds. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
44.
G. Pacelli Bessa Leandro F. Pessoa 《Bulletin of the Brazilian Mathematical Society》2014,45(2):243-265
Based on ideas of L. Alías, D. Impera and M. Rigoli developed in [13], we present a fairly general weak/Omori-Yau maximum principle for trace operators. We apply this version of maximum principle to generalize several higher order mean curvature estimates and to give an extension of Alias-Impera-Rigoli Slice Theorem of [13, Thm. 16 and 21], see Theorems 5 and 6. 相似文献
45.
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48.
49.
Hernán Pessoa‐Mahana R. Acevedo Ramiro Araya‐Maturana Claudio Saitz C. David Pessoa‐Mahana 《合成通讯》2013,43(20):3559-3567
New benzothiophene arylpiperazine derivatives 8 (a–f) were synthesized as potential serotoninergic agents with 5‐HT1A receptor affinity. Preparation of the derivatives was performed by treating N‐[2‐(chloromethyl)phenyl]‐4,7‐dimethoxybenzo[b]thiophene‐2‐carboxamide (7) with a series of substituted 4‐arylpiperazines. 相似文献
50.
Biosynthesis of Bromoroquefortines in a High Saline Medium by Penicillium chrysogenum,a Terrestrial Endophyte Collected from Coffea arabica
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José Vinicius da Silva Taicia Pacheco Fill Letícia Veras Lotufo Cláudia do Ó. Pessoa Edson Rodrigues‐Filho 《Helvetica chimica acta》2014,97(10):1345-1353
Roquefortine C ( 1 ) and 11‐bromoroquefortine C ( 4 ) were isolated from Penicillium chrysogenum, an endophyte obtained from green leaves of Coffea arabica, during induction experiments by adding halide salts to the culture media. In our studies, 11‐bromoroquefortine D and 11‐bromo‐17‐hydroxybromoroquefortine C were identified by LC/HR‐MS. It is the first time that bromoroquefortine C and D are described as halogenated natural products. These halo alkaloids were shown to be biosynthesized from brominated tryptophan as the biosynthetic precursor. Cytotoxic and antibiotic assays using roquefortine C and 11‐bromoroquefortine C showed that the presence of the 11‐Br substituent impairs some biological activities of this alkaloid. 相似文献