scholarly journals REMEDIAÇÃO DE PENTACLOROFENOL EM DOIS DIFERENTES TIPOS DE SOLO POR Sphingomonas chlorophenolica ATCC 39723

Author(s):  
Rosemeri Inês Dams ◽  
Graeme Paton ◽  
Ken Killham

O objetivo deste trabalho foi estudar a degradação de pentaclorophenol (PCP) por S. chlorophenolica em dois diferentes tipos de solo (arenoso e argiloso) na presença e ausência de plantas (trigo - Triticum aestivum). As concentrações de PCP foram determinadas mediante Cromatografia a Líquido de Alta Eficiência (CLAE). Os efeitos tóxicos de PCP foram estudados pelo monitoramento do crescimento das plantas (em peso, g) e medidas das raízes (cm). A biodegradação de PCP por S. chlorophenolica  nos dois tipos de solo foi acompanhada por análises de bioluminescência de Escherichia coli HB101 pUCD607. Contagens bacterianas foram realizadas em três meios de cultura: meio mineral para S. chlorophenolica, meio mineral para organismos degradadores/tolerantes ao PCP e ágar triptose caldo de soja para organismos heterotróficos. No solo argiloso com vegetação, a degradação de PCP ocorreu de forma mais rápida após a introdução de S. chlorophenolica que no solo sem plantas. O monitoramento do crescimento da planta mostrou o papel protetivo exercido pela S.chlorophenolica contra a toxicidade do PCP. O bioensaio confirmou que a toxicidade inicial causada pelo PCP diminuiu conforme o prosseguimento da degradação. No solo arenoso não houve degradação significativa. As determinações cromatográficas sugerem que mais de 75% do PCP estava adsorvido ao solo (não-disponível aos organismos degradadores). Não houve efeito deletério de PCP sobre o crescimento da planta nem sobre as raízes. Em ambos os solos houve aumento significativo nas populações bacterianas de Sphingomonas chlorophenolica, organismos PCP-degradadores/tolerantes e heterotróficos quando comparadas com as populações presentes nas raízes. Este estudo mostrou que a presença do inóculo Sphingomonas chlorophenolica melhorou a degradação de PCP em solo argiloso e seu papel protetor contra o efeito fitotóxico do PCP sobre plantas. A rizosfera de certas plantas pode ser importante para facilitar a degradação microbiana de pesticidas em solos com importantes implicações ao se utilizar a vegetação para estabilizar e remediar solos superficiais.

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2424 ◽  
Author(s):  
Tăbăcaru ◽  
Botezatu ◽  
Horincar ◽  
Furdui ◽  
Dinică

A family of fifteen quaternary ammonium salts (QAs), bearing the 1,2-bis(4-pyridyl)ethane core, were obtained using for the first time two different green methods, such as microwave (MW) and ultrasounds (US) irradiation, with very good yields and in much shorter times compared to the classical method, and an assay on their antimicrobial action against Escherichia coli (E. coli) was carried out. While 12 to 24 hours were required for complete alkylation of 1,2-bis(4-pyridyl)ethane by reactive halogenated derivatives in anhydrous solvent under reflux conditions, MW and US irradiation reduced the reaction time and the desired products were achieved in a few min. One of the aims of this study was to evaluate the antibacterial potential of the synthesized QAs against pathogenic bacteria, along with their impact on germination activity of wheat seeds (Triticum aestivum L.). The antibacterial activity of the QAs against Escherichia coli was explored by determining the minimum inhibitory concentration (MIC). The MIC values varied from 0.312 to 2.5 mg/mL, highlighting the lowest values attained for the derivatives containing methoxy, chlorine and benzofurane functional groups. The viability of aerobic bacteria was determined with the Tetrazolium/Formazan Test, a method that was found to be the best alternative approach with respect to the difuzimetric method. Seeds of Triticum aestivum L. were used for the evaluation of the germination indicators, such as seed germination (SG), the relative seed germination (RSG), the relative radicle growth (RRG), and the seed germination index (GI). The toxicity studies of QAs 1, 4 and 7, at two different concentrations, showed no inhibitory effect on seed germination.


1998 ◽  
Vol 252 (2) ◽  
pp. 314-324 ◽  
Author(s):  
Marie-Francoise Gautier ◽  
Valerie Lullien-Pellerin ◽  
Frederic de Lamotte-Guery ◽  
Anne Guirao ◽  
Philippe Joudrier

PLoS ONE ◽  
2017 ◽  
Vol 12 (2) ◽  
pp. e0171340 ◽  
Author(s):  
Xiaoyu Wang ◽  
Linsheng Zhang ◽  
Yane Zhang ◽  
Zhenqing Bai ◽  
Hao Liu ◽  
...  

2007 ◽  
Vol 12 (4) ◽  
pp. 426-432 ◽  
Author(s):  
Rosemeri I. Dams

O principal objetivo deste trabalho foi estudar a degradação de PCP por Sphingomonas chlorophenolicaem solo argiloso na presença e ausência de trigo. As concentrações de PCP foram determinadas através de Análises de Alta Performance de Cromatografia Líquida. Os efeitos tóxicos de PCP foram estudados através do monitoramento do crescimento das plantas. A biodegradação de PCP por S. chlorophenolica foi acompanhada por testes de bioluminescência de Escherichia coli HB101 pUCD607 e contagens bacterianas no solo e nas raízes. A degradação de PCP ocorreu de forma mais rápida no solo plantado e inoculado quando comparada ao solo sem plantas. Houve um aumento significativo nas populações dos organismos testados nas raízes quando comparadas com as populações presentes no solo. O monitoramento do crescimento da planta mostrou o papel protetor exercido pela S.chlorophenolica contra a toxicidade do PCP.


Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).


Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).


Author(s):  
Manfred E. Bayer

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.


Author(s):  
Manfred E. Bayer

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.


Author(s):  
A.J. Verkleij

Freeze-fracturing splits membranes into two helves, thus allowing an examination of the membrane interior. The 5-10 rm particles visible on both monolayers are widely assumed to be proteinaceous in nature. Most membranes do not reveal impressions complementary to particles on the opposite fracture face, if the membranes are fractured under conditions without etching. Even if it is considered that shadowing, contamination or fracturing itself might obscure complementary pits', there is no satisfactory explanation why under similar physical circimstances matching halves of other membranes can be visualized. A prominent example of uncomplementarity is found in the erythrocyte manbrane. It is wall established that band 3 protein and possibly glycophorin represents these nonccmplanentary particles. On the other hand a number of membrane types show pits opposite the particles. Scme well known examples are the ";gap junction',"; tight junction, the luminal membrane of the bladder epithelial cells and the outer membrane of Escherichia coli.


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