scholarly journals In vitro reconstitution of a hexagonal array with a surface layer protein synthesized by Bacillus subtilis harboring the surface layer protein gene from Bacillus brevis 47.

1989 ◽  
Vol 171 (12) ◽  
pp. 6747-6752 ◽  
Author(s):  
A Tsuboi ◽  
R Uchihi ◽  
H Engelhardt ◽  
H Hattori ◽  
S Shimizu ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Surface Layer ◽  
Protein Gene ◽  
Hexagonal Array ◽  
Bacillus Brevis ◽  
Surface Layer Protein ◽  
In Vitro Reconstitution

scholarly journals Evaluación del efecto biocontrolador de Bacillus spp., frente a Fusarium spp., bajo condiciones de invernadero en Rosmarinus officinalis L

Nova ◽  
2010 ◽  
Vol 8 (13) ◽  
pp. 63
Author(s):  
Diana Bautista ◽  
Lucía Constanza Corrales Ramírez MSC ◽  
Jairo Leonardo Cuervo Andrade PhD ◽  
Lady González ◽  
Marcela Guevara ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Megaterium ◽  
Rosmarinus Officinalis ◽  
Fusarium Spp ◽  
Bacillus Brevis ◽  
Fusarium Acuminatum ◽  
Bacillus Spp ◽  
Rosmarinus Officinalis L

El romero es una de las plantas aromáticas más importantes dentro del mercado de exportación  colombiano. El cultivo de esta planta se ve afectado por marchitez vascular producida por <em>Fusarium </em>spp. El objetivo principal de este trabajo fue establecer en el romero el efecto biocontrolador de <em>Bacillus </em>spp., frente a <em>Fusarium </em>spp., bajo condiciones de invernadero. Para ello se seleccionaron <em>Bacillus liqueniformis </em>(B1<em>), Bacillus subtilis </em>(B2), <em>Bacillus megaterium </em>(B14), <em>Bacillus brevis </em>(E2), aislados de rizósfera de plantas aromáticas, a los cuales se les realizaron pruebas de viabilidad, identificación enzimática manual y automatizada, y pruebas de antagonismo <em>in vitro </em>en medio PDA frente a <em>Fusarium acuminatum </em>aislado de las plantas de romero, comprobando la patogenicidad del hongo por postulados de Koch.<p>El ensayo se realizó con 30 plántulas de romero, un control negativo y uno positivo, bioensayos con sólo <em>Bacillus </em>spp., y tratamientos con <em>Bacillus </em>spp., más el patógeno. Para evaluar la severidad del patógeno y el comportamiento de las bacterias cada ensayo se realizó por triplicado y bajo condiciones de invernadero. En las pruebas de antagonismo <em>in vitro </em>B1 y B2 presentaron entre el 70–100% de inhibición del micelio y B14 y E2 entre el 40–69%. Los <em>Bacillus </em>spp<em>., </em>disminuyeron la severidad de la marchitez vascular en todos los ensayos; por la producción de sustancias antifúngicas facilitaron el aumento del peso seco de las hojas de las plantas al permitir la obtención de nutrientes y B14 aumentó la longitud de la raíz y el tallo. Se precisa secuenciar el aislamiento de <em>Fusarium, </em>para confirmar la especie.</p>

scholarly journals A Bacterial Surface Layer Protein Exploits Multi-step Crystallization for Rapid Self-assembly

2019 ◽  
Author(s):  
Jonathan Herrmann ◽  
Po-Nan Li ◽  
Fatemeh Jabbarpour ◽  
Anson C. K. Chan ◽  
Ivan Rajkovic ◽  
...  
Keyword(s):  
Surface Layer ◽  
Self Assembly ◽  
Molecular Mechanisms ◽  
Protein Crystallization ◽  
Crystal Nucleation ◽  
Time Resolved ◽  
Bacterial Surface ◽  
Surface Layer Protein

AbstractSurface layers (S-layers) are crystalline protein coats surrounding microbial cells. S-layer proteins (SLPs) regulate their extracellular self-assembly by crystallizing when exposed to an environmental trigger. However, molecular mechanisms governing rapid protein crystallization in vivo or in vitro are largely unknown. Here, we demonstrate that the C. crescentus SLP readily crystallizes into sheets in vitro via a calcium-triggered multi-step assembly pathway. This pathway involves two domains serving distinct functions in assembly. The C-terminal crystallization domain forms the physiological 2D crystal lattice, but full-length protein crystallizes multiple orders of magnitude faster due to the N-terminal nucleation domain. Observing crystallization using time-resolved electron cryo-microscopy (Cryo-EM) reveals a crystalline intermediate wherein N-terminal nucleation domains exhibit motional dynamics with respect to rigid lattice-forming crystallization domains. Dynamic flexibility between the two domains rationalizes efficient S-layer crystal nucleation on the curved cellular surface. Rate enhancement of protein crystallization by a discrete nucleation domain may enable engineering of kinetically controllable self-assembling 2D macromolecular nanomaterials.Significance StatementMany microbes assemble a crystalline protein layer on their outer surface as an additional barrier and communication platform between the cell and its environment. Surface layer proteins efficiently crystallize to continuously coat the cell and this trait has been utilized to design functional macromolecular nanomaterials. Here, we report that rapid crystallization of a bacterial surface layer protein occurs through a multi-step pathway involving a crystalline intermediate. Upon calcium-binding, sequential changes occur in the structure and arrangement of the protein, which are captured by time-resolved small angle x-ray scattering and transmission electron cryo-microscopy. We demonstrate that a specific domain is responsible for enhancing the rate of self-assembly, unveiling possible evolutionary mechanisms to enhance the kinetics of 2D protein crystallization in vivo.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

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