Macrophages are one of the principal immune effector cells that play essential roles as secretory, phagocytic, and antigen-presenting cells in the immune system. In this study, we address the issue of cytotoxicity and immunogenic effects of gold nanoparticles on RAW264.7 macrophage cells. The cytotoxicity of gold nanoparticles has been correlated with a detailed study of their endocytotic uptake using various microscopy tools such as atomic force microscopy (AFM), confocal-laser-scanning microscopy (CFLSM), and transmission electron microscopy (TEM). Our findings suggest that Au(0) nanoparticles are not cytotoxic, reduce the production of reactive oxygen and nitrite species, and do not elicit secretion of proinflammatory cytokines TNF-α and IL1-β, making them suitable candidates for nanomedicine. AFM measurements suggest that gold nanoparticles are internalized inside the cell via a mechanism involving pinocytosis, while CFLSM and TEM studies indicate their internalization in lysosomal bodies arranged in ...

Biocompatibility of gold nanoparticles and their endocytotic fate inside the cellular compartment: a microscopic overview.

Surface-functionalized silica nanoparticles can deliver DNA and drugs into animal cells and tissues. However, their use in plants is limited by the cell wall present in plant cells. Here we show a honeycomb mesoporous silica nanoparticle (MSN) system with 3-nm pores that can transport DNA and chemicals into isolated plant cells and intact leaves. We loaded the MSN with the gene and its chemical inducer and capped the ends with gold nanoparticles to keep the molecules from leaching out. Uncapping the gold nanoparticles released the chemicals and triggered gene expression in the plants under controlled-release conditions. Further developments such as pore enlargement and multifunctionalization of these MSNs may offer new possibilities in target-specific delivery of proteins, nucleotides and chemicals in plant biotechnology.

Mesoporous silica nanoparticles deliver DNA and chemicals into plants

A green light for engineered algae: redirecting metabolism to fuel a biotechnology revolution

Systemic acquired resistance (SAR) is a broad-spectrum resistance in plants that involves the upregulation of a battery of pathogenesis-related (PR) genes. NPR1 is a key regulator in the signal transduction pathway that leads to SAR. Mutations in NPR1 result in a failure to induce PR genes in systemic tissues and a heightened susceptibility to pathogen infection, whereas overexpression of the NPR1 protein leads to increased induction of the PR genes and enhanced disease resistance. We analyzed the subcellular localization of NPR1 to gain insight into the mechanism by which this protein regulates SAR. An NPR1–green fluorescent protein fusion protein, which functions the same as the endogenous NPR1 protein, was shown to accumulate in the nucleus in response to activators of SAR. To control the nuclear transport of NPR1, we made a fusion of NPR1 with the glucocorticoid receptor hormone binding domain. Using this steroid-inducible system, we clearly demonstrate that nuclear localization of NPR1 is essential for its activity in inducing PR genes.

Nuclear Localization of NPR1 Is Required for Activation of PR Gene Expression

Renewable fuels from algae: An answer to debatable land based fuels

The biolistic process is still rapidly evolving. We do not anticipate further major improvements in biolistic apparatus. There will probably still be further major improvements in particles, DNA coating, and vectors, as well as significant further advances in understanding of biological determinants of cell penetration and survival. The technology has currently reached the point at which it can be readily and reliably used for a wide range of applications. Given the information presented in this chapter, new applications can be optimized fairly readily.

Optimizing the biolistic process for different biological applications.

Publisher Summary
This chapter discusses biolistic process optimization for different biological applications. The biolistic process employs high-velocity microprojectiles to deliver nucleic acids and other substances into intact cells and tissues. This process is also called the microprojectile bombardment method, the gene gun method and the particle acceleration method. The biolistic process was developed as a means to deliver foreign genes into the nuclear genome of higher plants. It has proven to be effective even in very small cell types, and has therefore been useful in transforming diverse microbial species. These include microbial eukaryotes, prokaryotes, and obligate fungal pathogens. The basic features that are considered while using the biolistic process are particle accelerator parameters, microprojectile parameters, biological parameters, and experimental design. The chapter additionally highlights the several biological parameters that are important for successful biolistic transformation. First, one must have an appropriate gene construct with a promoter that is strong and that will express in desired target tissue. Second, the target cells must be in a state receptive to transformation. Third, there must be high rates of particle penetration and cell survival and growth after bombardment.

F.D. Smith

Papers

Optimizing the biolistic process for different biological applications.

[32] – Optimizing the Biolistic Process for Different Biological Applications