Dataset Information

Microscopic mechanism of nanocrystal formation from solution by cluster aggregation and coalescence.

ABSTRACT: Solute-cluster aggregation and particle fusion have recently been suggested as alternative routes to the classical mechanism of nucleation from solution. The role of both processes in the crystallization of an aqueous electrolyte under controlled salt addition is here elucidated by molecular dynamics simulation. The time scale of the simulation allows direct observation of the entire crystallization pathway, from early events in the prenucleation stage to the formation of a nanocrystal in equilibrium with concentrated solution. The precursor originates in a small amorphous aggregate stabilized by hydration forces. The core of the nucleus becomes crystalline over time and grows by coalescence of the amorphous phase deposited at the surface. Imperfections of ion packing during coalescence promote growth of two conjoint crystallites. A parameter of order and calculated cohesive energies reflect the increasing crystalline order and stress relief at the grain boundary. Cluster aggregation plays a major role both in the formation of the nucleus and in the early stages of postnucleation growth. The mechanism identified shares common features with nucleation of solids from the melt and of liquid droplets from the vapor.

SUBMITTER: Hassan SA

PROVIDER: S-EPMC3073013 | biostudies-other | 2011 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Listeria monocytogenes (Lm) cells can attach to both cantaloupe surface and food contact surfaces and promote biofilm growth. This study was to understand the impact of cantaloupe juice on the physiology and transcriptome of Lm planktonic cells and biofilm cells grown on stainless steel coupons using confocal laser scanning microscopy (CLSM), Cryo-Scanning Electron Microscopy (Cryo-SEM) and RNA Seq technology. Lm showed a strong autoaggregation phenotype when grown in cantaloupe juice at room temperature. It is interesting to note that Lm formed significantly more biofilms on stainless steel (SS) coupons when grown in cantaloupe juice than in TSB. SEM images revealed a different attachment profile of Lm on SS coupons. In TSB, Lm cells were mainly found in scratches/groves of the metal surface, whereas, in cantaloupe juice they attached to the smooth surface as well. Interestingly, Lm planktonic and biofilm cells in cantaloupe juice showed an elongated cell shape which might be a stress-induced phenotype in cantaloupe juice. Cantaloupe juice induced a distinct transcriptional profile of biofilm and planktonic cells of Lm from TSB. Functional annotation indicated that the significantly differentially expressed genes (DEGs, Padj < 0.05, log2foldchange ≥ 1) from the comparison mainly participated in metabolism, signaling and stress response. Notably, certain pathways downregulated for planktonic cells were significantly upregulated for biofilm cells in cantaloupe juice compared to TSB, including ABC transporters, two-component system, quorum sensing, chemotaxis, and flagellar assembly. These data highlighted the interaction of Lm with food matrix (i.e., cantaloupe) and the role of food matrix on Lm survival and adaptation. These results provided the basis for future functional characterization of genes with potential roles in biofilm formation and persistence of Lm in cantaloupe juice, as well as for development of mitigation practices for Lm biofilms on produce and food contact surfaces.

Dataset Information

Microscopic mechanism of nanocrystal formation from solution by cluster aggregation and coalescence.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets