125 research outputs found
Initial in vitro evaluations of antibacterial activities of glucosinolate enzymatic hydrolysis products against plant pathogenic bacteria
Aims: The aim of the study was to evaluate the in vitro antibacterial effects of
glucosinolate hydrolysis products (GHP) against plant pathogenic micro-organisms
namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas
cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas
juglandis.
Methods and Results: Using a disc diffusion assay, seven different doses of 10
GHP were tested against each bacteria. The results showed that the isothiocyanates
were potent antibacterials, whilst the other GHP were much less efficient.
Moreover, the antibacterial effects were dose-dependent, increasing with the
dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest
inhibitory effects. The overall results show a great potential for using the
isothiocyanates as an alternative tool to control undesired bacterial growth in
plants.
Conclusions: Glucosinolate hydrolysis products and more specifically the
isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate
Mix and sulforaphane, were effective phytochemicals against the in vitro
growth of the phytopathogenic bacteria. The antibacterial activity exhibited by
these phytochemicals reinforces their potential as alternatives to the traditional
chemical control of phytopathogenic bacteria.
Significance and Impact of the Study: This current in vitro study is the first
providing comparative data on GHP as potential control agents for plant
pathogenic bacteria. However, more studies are needed to determine their
possible allelopathic impacts e.g. inhibition of plant growth and negative effects
on beneficial soil bacteria and fungi (mycorrhizae
An alternative order parameter for the 4-state Potts model
We have investigated the dynamic critical behavior of the two-dimensional
4-state Potts model using an alternative order parameter first used by
Vanderzande [J. Phys. A: Math. Gen. \textbf{20}, L549 (1987)] in the study of
the Z(5) model. We have estimated the global persistence exponent by
following the time evolution of the probability that the considered
order parameter does not change its sign up to time . We have also obtained
the critical exponents , , , and using this alternative
definition of the order parameter and our results are in complete agreement
with available values found in literature.Comment: 6 pages, 6 figure
ResĂduos de Serviços de SaĂșde Gerados em Unidades de SaĂșde de Pequeno Porte no MunicĂpio de JaĂș- SP: Geração e Disposição Final
Considerando a quantidade expressiva de resĂduos gerados pelas unidades de saĂșde de pequeno porte, a preocupação crescente com o gerenciamento destes resĂduos e a falta de investigaçÔes sobre o tema, este trabalho caracteriza a geração e disposição final dos ResĂduos de Serviços de SaĂșde gerados em unidades de saĂșde de pequeno porte, no municĂpio de JaĂș-SP
Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry
In this paper we examine the role of crystal chemistry factors in creating
conditions for formation of magnetoelectric ordering in BiFeO3. It is generally
accepted that the main reason of the ferroelectric distortion in BiFeO3 is
concerned with a stereochemical activity of the Bi lone pair. However, the lone
pair is stereochemically active in the paraelectric orthorhombic beta-phase as
well. We demonstrate that a crucial role in emerging of phase transitions of
the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order
types belongs to the change of the degree of the lone pair stereochemical
activity - its consecutive increase with the temperature decrease. Using the
structural data, we calculated the sign and strength of magnetic couplings in
BiFeO3 in the range from 945 C down to 25 C and found the couplings, which
undergo the antiferromagnetic-ferromagnetic transition with the temperature
decrease and give rise to the antiferromagnetic ordering and its delay in
regard to temperature, as compared to the ferroelectric ordering. We discuss
the reasons of emerging of the spatially modulated spin structure and its
suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table
Produção orgĂąnica de calĂȘndula: um estudo de caso.
Apresenta-se caracterização do processo de produção agrĂcola orgĂąnica de Calendula officinalis L. no Estado de Santa Catarina, evidenciando particularidades e discrepĂąncias frente aos modelos jĂĄ descritos na literatura especializada, a partir de visitas a campo, observação participante e entrevistas com um produtor de plantas medicinais. Identificaram-se como principais particularidades a saĂșde na agricultura familiar, demonstrada pela prĂĄtica da cultura orgĂąnica, alĂ©m do controle de pragas e manuseio da produção. Os principais problemas ou divergĂȘncias evidenciados foram: caracterĂsticas do solo; Ă©poca de plantio da calĂȘndula e suas etapas posteriores, como transplante e floração. Aspectos da colheita foram discrepantes quanto ao perĂodo do dia indicado para o procedimento, bem como a ausĂȘncia de informaçÔes do produtor quanto Ă existĂȘncia de outros incentivos governamentais ao setor agrĂcola. Recomenda-se aos extensionistas rurais e/ou instituiçÔes competentes que busquem orientar os produtores orgĂąnicos de calĂȘndula para promover a adequação das prĂĄticas de cultivo dessa espĂ©cie medicinal
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